diff --git a/lib/Connection.js b/lib/Connection.js
index 600c956..fda9dc0 100644
--- a/lib/Connection.js
+++ b/lib/Connection.js
@@ -2,10 +2,14 @@
 
 const Promise = require("bluebird");
 const defaultValue = require("default-value");
+const asExpression = require("as-expression");
+const matchValue = require("match-value");
+const unreachable = require("@joepie91/unreachable");
 
 const { command, unsafeRaw, already7Bit } = require("./util/command");
 const pInterval = require("./util/p-interval");
 const createFetchTaskTracker = require("./util/fetch-task");
+const createBoxTreeBuilder = require("./util/box-tree-builder");
 
 var tls = require('tls'),
 	Socket = require('net').Socket,
@@ -1234,25 +1238,166 @@ Object.defineProperty(Connection.prototype, 'seq', { get: function() {
 	};
 }});
 
+function createCommandHandlers(rules) {
+	let untaggedHandlers = new Map();
+	let taggedHandlers = new Map();
+
+	for (let [ types, options ] of Object.entries(rules)) {
+		let parsedTypes = types
+			.split(/\s*\s*/)
+			.map((type) => type.toUpperCase());
+
+		for (let type of parsedTypes) {
+			if (options.untagged != null) {
+				untaggedHandlers.set(type, options.untagged);
+			}
+
+			if (options.tagged != null) {
+				taggedHandlers.set(type, options.tagged);
+			}
+		}
+	}
+
+	// REFACTOR: Eventually remove `.call(this` hackery
+	return {
+		canHandleUntagged: function (request) {
+			return untaggedHandlers.has(request.type.toUpperCase());
+		},
+		canHandleTagged: function (request) {
+			return taggedHandlers.has(request.type.toUpperCase());
+		},
+		handleUntagged: function (request, data) {
+			let handler = untaggedHandlers.get(request.type.toUpperCase());
+			return handler.call(this, request, data);
+		},
+		handleTagged: function (request, data) {
+			let handler = taggedHandlers.get(request.type.toUpperCase());
+			return handler.call(this, request, data);
+		}
+	};
+}
+
+let commandHandlers = createCommandHandlers({
+	"LIST, XLIST, LSUB": {
+		untagged: function (request, { payload }) {
+			if (request.delimiter === undefined) {
+				request.delimiter = payload.delimiter;
+			} else {
+				if (request.boxBuilder == null) {
+					request.boxBuilder = createBoxTreeBuilder();
+				}
+	
+				request._curReq.boxBuilder.add(payload);
+			}
+		},
+		tagged: function (request, _) {
+			// FIXME: Check request types for correctness
+			let boxTree = (request.boxBuilder != null)
+				? request.boxBuilder.done()
+				: {}; // No response items were received
+
+			request.legacyArgs.push(boxTree);
+			request.responseData.boxTree = boxTree;
+		}
+	},
+	"ID": {
+		untagged: function (request, { payload }) {
+			// https://datatracker.ietf.org/doc/html/rfc2971
+			// Used for communicating server/client name, version, etc.
+			request.responseData.serverVersion = payload;
+			request.legacyArgs.push(payload);
+		}
+	}
+});
+
+
+
+
+
 // type: type,
-// num: num,
+// num: num, -- sequence number of the affected nessage, used for FETCH and EXPUNGE only (message-data) and maybe RECENT and EXISTS (mailbox-data)?
 // textCode: textCode,
 // text: val
 
-Connection.prototype._resUntagged = function({ type, num, textCode, text: payload }) {
+// NOTE: responseData is meant to contain machine-readable data, payload is meant to contain human-readable data, but in practice payload is also often machine-parsed
+Connection.prototype._resUntagged = function({ type, num: sequenceNumber, textCode: responseData, text: payload }) {
+	// console.log("resUntagged", { type, num: sequenceNumber, payload, textCode: responseData });
 	var i, len, box, destinationKey;
 
-	if (type === 'bye') {
+	if (this._curReq != null && commandHandlers.canHandleUntagged(this._curReq)) {
+		// FIXME: Include other fields
+		commandHandlers.handleUntagged.call(this, this._curReq, { sequenceNumber, payload });
+	} else if (type === 'bye') {
 		this._sock.end();
 	} else if (type === 'namespace') {
 		this.namespaces = payload;
-	} else if (type === 'id') {
-		this._curReq.cbargs.push(payload);
 	} else if (type === 'capability') {
 		this._caps = payload.map((v) => v.toUpperCase());
 	} else if (type === 'preauth') {
 		this.state = 'authenticated';
-	} else if (type === 'sort' || type === 'thread' || type === 'esearch') {
+	} else if (type === 'expunge') {
+		if (this._box) {
+			if (this._box.messages.total > 0) {
+				this._box.messages.total -= 1;
+			}
+
+			this.emit('expunge', sequenceNumber);
+		}
+	} else if (type === 'ok') {
+		if (this.state === 'connected' && !this._curReq) {
+			this._login();
+		} else if (typeof responseData === 'string' && responseData.toUpperCase() === 'ALERT') {
+			this.emit('alert', payload);
+		} else if (this._curReq && responseData && (RE_OPENBOX.test(this._curReq.type))) {
+			// we're opening a mailbox
+
+			if (!this._box) {
+				this._resetCurrentBox();
+			}
+
+			let destinationKey = (responseData.key != null)
+				? responseData.key.toUpperCase()
+				: responseData;
+
+			if (destinationKey === 'UIDVALIDITY') {
+				this._box.uidvalidity = responseData.val;
+			} else if (destinationKey === 'UIDNEXT') {
+				this._box.uidnext = responseData.val;
+			} else if (destinationKey === 'HIGHESTMODSEQ') {
+				this._box.highestmodseq = ''+responseData.val;
+			} else if (destinationKey === 'PERMANENTFLAGS') {
+				var idx, permFlags, keywords;
+				this._box.permFlags = permFlags = responseData.val;
+
+				if ((idx = this._box.permFlags.indexOf('\\*')) > -1) {
+					this._box.newKeywords = true;
+					permFlags.splice(idx, 1);
+				}
+
+				this._box.keywords = keywords = permFlags.filter((f) => f[0] !== '\\');
+
+				for (i = 0, len = keywords.length; i < len; ++i) {
+					permFlags.splice(permFlags.indexOf(keywords[i]), 1);
+				}
+			} else if (destinationKey === 'UIDNOTSTICKY') {
+				this._box.persistentUIDs = false;
+			} else if (destinationKey === 'NOMODSEQ') {
+				this._box.nomodseq = true;
+			}
+		} else if (typeof responseData === 'string' && responseData.toUpperCase() === 'UIDVALIDITY') {
+			this.emit('uidvalidity', payload);
+		}
+	} else if (type === "esearch") {
+		// https://datatracker.ietf.org/doc/html/rfc4731 / https://datatracker.ietf.org/doc/html/rfc7377
+		Object.assign(this._curReq.responseData, payload); // Protocol-defined attributes. TODO: Improve the key names for this? Or is there extensibility?
+		this._curReq.cbargs.push(payload);
+	} else if (type === "sort") {
+		// https://datatracker.ietf.org/doc/html/rfc5256
+		this._curReq.responseData.UIDs = payload;
+		this._curReq.cbargs.push(payload);
+	} else if (type === 'thread') {
+		// https://datatracker.ietf.org/doc/html/rfc5256
+		this._curReq.responseData.threads = payload; // FIXME: Work out the exact format
 		this._curReq.cbargs.push(payload);
 	} else if (type === 'search') {
 		if (payload.results !== undefined) {
@@ -1263,23 +1408,24 @@ Connection.prototype._resUntagged = function({ type, num, textCode, text: payloa
 			this._curReq.cbargs.push(payload);
 		}
 	} else if (type === 'quota') {
-		var cbargs = this._curReq.cbargs;
-		if (!cbargs.length) {
-			cbargs.push([]);
-		}
+		let responseData = this._curReq.responseData;
+		if (responseData.quota == null) { responseData.quota = []; };
+		responseData.quota.push(payload);
 
+		let cbargs = this._curReq.cbargs;
+		if (cbargs.length === 0) { cbargs.push([]); }
 		cbargs[0].push(payload);
 	} else if (type === 'recent') {
 		if (!this._box && RE_OPENBOX.test(this._curReq.type)) {
-			this._createCurrentBox();
+			this._resetCurrentBox();
 		}
 
 		if (this._box) {
-			this._box.messages.new = num;
+			this._box.messages.new = sequenceNumber;
 		}
 	} else if (type === 'flags') {
 		if (!this._box && RE_OPENBOX.test(this._curReq.type)) {
-			this._createCurrentBox();
+			this._resetCurrentBox();
 		}
 
 		if (this._box) {
@@ -1296,124 +1442,17 @@ Connection.prototype._resUntagged = function({ type, num, textCode, text: payloa
 		}
 	} else if (type === 'exists') {
 		if (!this._box && RE_OPENBOX.test(this._curReq.type)) {
-			this._createCurrentBox();
+			this._resetCurrentBox();
 		}
 
 		if (this._box) {
-			var prev = this._box.messages.total, now = num;
+			var prev = this._box.messages.total, now = sequenceNumber;
 			this._box.messages.total = now;
 			if (now > prev && this.state === 'authenticated') {
 				this._box.messages.new = now - prev;
 				this.emit('mail', this._box.messages.new);
 			}
 		}
-	} else if (type === 'expunge') {
-		if (this._box) {
-			if (this._box.messages.total > 0) {
-				--this._box.messages.total;
-			}
-
-			this.emit('expunge', num);
-		}
-	} else if (type === 'ok') {
-		if (this.state === 'connected' && !this._curReq) {
-			this._login();
-		} else if (typeof textCode === 'string' && textCode.toUpperCase() === 'ALERT') {
-			this.emit('alert', payload);
-		}
-		else if (this._curReq
-			&& textCode
-			&& (RE_OPENBOX.test(this._curReq.type))) {
-			// we're opening a mailbox
-
-			if (!this._box) {
-				this._createCurrentBox();
-			}
-
-			if (textCode.key) {
-				destinationKey = textCode.key.toUpperCase();
-			} else {
-				destinationKey = textCode;
-			}
-
-			if (destinationKey === 'UIDVALIDITY') {
-				this._box.uidvalidity = textCode.val;
-			} else if (destinationKey === 'UIDNEXT') {
-				this._box.uidnext = textCode.val;
-			} else if (destinationKey === 'HIGHESTMODSEQ') {
-				this._box.highestmodseq = ''+textCode.val;
-			} else if (destinationKey === 'PERMANENTFLAGS') {
-				var idx, permFlags, keywords;
-				this._box.permFlags = permFlags = textCode.val;
-
-				if ((idx = this._box.permFlags.indexOf('\\*')) > -1) {
-					this._box.newKeywords = true;
-					permFlags.splice(idx, 1);
-				}
-
-				this._box.keywords = keywords = permFlags.filter((f) => f[0] !== '\\');
-
-				for (i = 0, len = keywords.length; i < len; ++i) {
-					permFlags.splice(permFlags.indexOf(keywords[i]), 1);
-				}
-			} else if (destinationKey === 'UIDNOTSTICKY')
-				this._box.persistentUIDs = false;
-			else if (destinationKey === 'NOMODSEQ')
-				this._box.nomodseq = true;
-		} else if (typeof textCode === 'string'
-							 && textCode.toUpperCase() === 'UIDVALIDITY')
-			this.emit('uidvalidity', payload);
-	} else if (type === 'list' || type === 'lsub' || type === 'xlist') {
-		if (this.delimiter === undefined) {
-			this.delimiter = payload.delimiter;
-		} else {
-			if (this._curReq.cbargs.length === 0) {
-				this._curReq.cbargs.push({});
-			}
-
-			box = {
-				attribs: payload.flags,
-				delimiter: payload.delimiter,
-				children: null,
-				parent: null
-			};
-
-			for (i = 0, len = SPECIAL_USE_ATTRIBUTES.length; i < len; ++i) {
-				if (box.attribs.indexOf(SPECIAL_USE_ATTRIBUTES[i]) > -1) {
-					box.special_use_attrib = SPECIAL_USE_ATTRIBUTES[i];
-				}
-			}
-
-			var name = payload.name,
-				curChildren = this._curReq.cbargs[0];
-
-			if (box.delimiter) {
-				var path = name.split(box.delimiter),
-					parent = null;
-
-				name = path.pop();
-
-				for (i = 0, len = path.length; i < len; ++i) {
-					if (!curChildren[path[i]]) {
-						curChildren[path[i]] = {};
-					}
-
-					if (!curChildren[path[i]].children) {
-						curChildren[path[i]].children = {};
-					}
-
-					parent = curChildren[path[i]];
-					curChildren = curChildren[path[i]].children;
-				}
-				box.parent = parent;
-			}
-
-			if (curChildren[name]) {
-				box.children = curChildren[name].children;
-			}
-
-			curChildren[name] = box;
-		}
 	} else if (type === 'status') {
 		let attrs = defaultValue(payload.attrs, {});
 
@@ -1437,57 +1476,59 @@ Connection.prototype._resUntagged = function({ type, num, textCode, text: payloa
 	 } else if (type === 'fetch') {
 		if (/^(?:UID )?FETCH/.test(this._curReq.fullcmd)) {
 			// FETCH response sent as result of FETCH request
-			let task = this._curReq.fetchCache.get(num);
+			let task = this._curReq.fetchCache.get(sequenceNumber);
 
 			// FIXME: Refactor, probably make the task itself an event emitter
 			if (task == null) {
-				task = this._curReq.fetchCache.create(num, this._curReq.fetching.slice());
-				this._curReq.bodyEmitter.emit('message', task.emitter, num);
+				task = this._curReq.fetchCache.create(sequenceNumber, this._curReq.fetching.slice());
+				this._curReq.bodyEmitter.emit('message', task.emitter, sequenceNumber);
 			}
 
 			task.processFetchResponse(payload);
 		} else {
 			// FETCH response sent as result of STORE request or sent unilaterally,
 			// treat them as the same for now for simplicity
-			this.emit('update', num, payload);
+			this.emit('update', sequenceNumber, payload);
 		}
 	}
 };
 
-Connection.prototype._resTagged = function(info) {
-	var req = this._curReq;
+Connection.prototype._resTagged = function({ type, tagnum, text: payload, textCode: responseCode }) {
+	// console.log("resTagged", { type, tagnum, payload, textCode: responseCode });
+	// REFACTOR: textCode: either just the key, or a {key, val} object
+	var request = this._curReq;
 
-	if (req != null) {
+	if (request != null) {
 		var err;
 		this._curReq = undefined;
 
-		if (info.type === 'no' || info.type === 'bad') {
-			// TODO: Can info.text be an empty string?
-			let errorText = defaultValue(info.text, req.oauthError);
+		if (type === 'no' || type === 'bad') {
+			// TODO: Can text be an empty string?
+			let errorText = defaultValue(payload, request.oauthError);
 
 			err = Object.assign(new Error(errorText), {
-				type: info.type,
-				text: info.textCode,
+				type: type,
+				text: responseCode,
 				source: "protocol"
 			});
 		} else if (this._box != null) {
-			if (req.type === 'EXAMINE' || req.type === 'SELECT') {
+			if (request.type === 'EXAMINE' || request.type === 'SELECT') {
 				this._box.readOnly = (
-					typeof info.textCode === 'string'
-					&& info.textCode.toUpperCase() === 'READ-ONLY'
+					typeof responseCode === 'string'
+					&& responseCode.toUpperCase() === 'READ-ONLY'
 				);
 			}
 
 			// According to RFC 3501, UID commands do not give errors for
 			// non-existant user-supplied UIDs, so give the callback empty results
 			// if we unexpectedly received no untagged responses.
-			if (RE_UIDCMD_HASRESULTS.test(req.fullcmd) && req.cbargs.length === 0) {
-				req.cbargs.push([]);
+			if (RE_UIDCMD_HASRESULTS.test(request.fullcmd) && request.cbargs.length === 0) {
+				request.cbargs.push([]);
 			}
 		}
 
-		if (req.bodyEmitter) {
-			var bodyEmitter = req.bodyEmitter;
+		if (request.bodyEmitter != null) {
+			var bodyEmitter = request.bodyEmitter;
 
 			if (err) {
 				bodyEmitter.emit('error', err);
@@ -1497,19 +1538,48 @@ Connection.prototype._resTagged = function(info) {
 				bodyEmitter.emit('end');
 			});
 		} else {
-			req.cbargs.unshift(err);
-
-			if (info.textCode && info.textCode.key) {
-				var key = info.textCode.key.toUpperCase();
-				if (key === 'APPENDUID') { // [uidvalidity, newUID]
-					req.cbargs.push(info.textCode.val[1]);
-				} else if (key === 'COPYUID') { // [uidvalidity, sourceUIDs, destUIDs]
-					req.cbargs.push(info.textCode.val[2]);
+			let extraArguments = asExpression(() => {
+				if (responseCode != null && responseCode.key != null) {
+					return matchValue(responseCode.key.toUpperCase(), {
+						// [uidvalidity, newUID]
+						APPENDUID: [ responseCode.val[1] ],
+						// [uidvalidity, sourceUIDs, destUIDs]
+						COPYUID: [ responseCode.val[2] ],
+						_: []
+					});
+				} else {
+					return [];
 				}
+			});
+
+			if (responseCode != null && responseCode.key != null) {
+				// FIXME: This eventually should replace the extraArguments array stuff
+				matchValue(responseCode.key.toUpperCase(), {
+					APPENDUID: () => {
+						request.responseData.newUID = responseCode.val[1];
+					},
+					COPYUID: () => {
+						// FIXME: Parsing? Looks like it will be multiple items
+						request.responseData.destinationUIDs = responseCode.val[2];
+					}
+				});
 			}
 
-			if (req.cb != null) {
-				req.cb.apply(this, req.cbargs);
+			if (commandHandlers.canHandleTagged(request)) {
+				// FIXME: Add other fields with a sensible name
+				commandHandlers.handleTagged.call(this, request, { payload });
+			}
+
+			// console.dir({ done: request.cbargs }, { depth: null, colors: true });
+
+			if (request.cb2 != null) {
+				request.cb.apply(this, request.responseData);
+			} else if (request.cb != null) {
+				request.cb.apply(this, [
+					err,
+					... request.cbargs,
+					... extraArguments
+				]);
 			}
 		}
 
@@ -1528,7 +1598,7 @@ Connection.prototype._resTagged = function(info) {
 	}
 };
 
-Connection.prototype._createCurrentBox = function() {
+Connection.prototype._resetCurrentBox = function() {
 	this._box = {
 		name: '',
 		flags: [],
@@ -1744,25 +1814,31 @@ Connection.prototype._sockWriteAppendData = function(appendData)
 	this._sock.write(CRLF);
 };
 
-Connection.prototype._enqueue = function(fullcmd, promote, cb) {
+Connection.prototype._enqueue = function(fullcmd, promote, cb, newAPI) {
 	// TODO: Remove variability
 	if (typeof promote === 'function') {
 		cb = promote;
 		promote = false;
 	}
 
-	var info = {
-				type: fullcmd.match(RE_CMD)[1],
-				fullcmd: fullcmd,
-				cb: cb,
-				cbargs: []
-			},
-			self = this;
+	var request = {
+		type: fullcmd.match(RE_CMD)[1],
+		fullcmd: fullcmd,
+		cb: (newAPI) ? null : cb,
+		cb2: (newAPI) ? cb : null,
+		cbargs: [],
+		responseData: {}
+	};
+
+	// Alias
+	request.legacyArgs = request.cbargs;
+
+	var self = this;
 
 	if (promote) {
-		this._queue.unshift(info);
+		this._queue.unshift(request);
 	} else {
-		this._queue.push(info);
+		this._queue.push(request);
 	}
 
 	if (!this._curReq
@@ -1796,7 +1872,7 @@ Connection.prototype._enqueue2 = function (command, options = {}) {
 		return this._enqueueAsync(string, insertInFront);
 	} else {
 		// TODO: Use `unreachable`
-		throw new Error(`Must use a command template string`);
+		throw unreachable(`Must use a command template string`);
 	}
 };
 
diff --git a/lib/Parser.js b/lib/Parser.js
index 2ec35b6..aa183f4 100644
--- a/lib/Parser.js
+++ b/lib/Parser.js
@@ -1,3 +1,5 @@
+/* eslint-disable */ /* FIXME */
+
 var EventEmitter = require('events').EventEmitter,
     ReadableStream = require('stream').Readable
                      || require('readable-stream').Readable,
diff --git a/lib/util/box-tree-builder.js b/lib/util/box-tree-builder.js
new file mode 100644
index 0000000..3ec1fe2
--- /dev/null
+++ b/lib/util/box-tree-builder.js
@@ -0,0 +1,48 @@
+"use strict";
+
+const lastItem = require("last-item");
+const createNamedTreeBuilder = require("./named-tree-builder");
+
+const specialUseAttributes = new Set([
+	'\\All',
+	'\\Archive',
+	'\\Drafts',
+	'\\Flagged',
+	'\\Important',
+	'\\Junk',
+	'\\Sent',
+	'\\Trash'
+]);
+
+// TODO: Eventually make this progressively updateable so that the results of multiple LIST commands can be combined over time?
+
+module.exports = function createBoxTreeBuilder() {
+	let treeBuilder = createNamedTreeBuilder({
+		childrenKey: "children",
+		parentKey: "parent",
+		treatRootAsParent: false
+	});
+
+	return {
+		add: function (item) {
+			let { flags, delimiter } = item;
+
+			let path = (delimiter != null)
+				? item.name.split(delimiter)
+				: [ item.name ];
+
+			treeBuilder.add(path, {
+				name: lastItem(path),
+				path: path,
+				attributes: flags,
+				delimiter: delimiter,
+				specialUseAttribute: flags.find((attribute) => specialUseAttributes.has(attribute)),
+				children: null,
+				parent: null
+			});
+		},
+		done: function () {
+			return treeBuilder.done().children;
+		}
+	};
+};
diff --git a/lib/util/named-tree-builder.js b/lib/util/named-tree-builder.js
new file mode 100644
index 0000000..dcd9da4
--- /dev/null
+++ b/lib/util/named-tree-builder.js
@@ -0,0 +1,80 @@
+"use strict";
+
+const defaultValue = require("default-value");
+const asExpression = require("as-expression");
+
+// FIXME: Move to stand-alone package, clearly document that it is not order-sensitive
+
+function ensureObject(object, property) {
+	if (object[property] == null) {
+		object[property] = {};
+	}
+}
+
+module.exports = function createNamedTreeBuilder(options = {}) {
+	let parentKey = options.parentKey;
+	let childrenKey = options.childrenKey;
+	let treatRootAsParent = defaultValue(options.treatRootAsParent, true);
+	let root = {};
+	let done = false;
+
+	return {
+		add: function (path, item) {
+			if (done === true) {
+				throw new Error(`done() was called on the builder; no further modifications are possible`);
+			} else {
+				let lastItem = root;
+
+				for (let i = 0; i < path.length; i++) {
+					let segment = path[i];
+					
+					// eslint-disable-next-line no-loop-func
+					let childrenContainer = asExpression(() => {
+						if (childrenKey != null) {
+							ensureObject(lastItem, childrenKey);
+							return lastItem[childrenKey];
+						} else {
+							return lastItem;
+						}
+					});
+					
+					ensureObject(childrenContainer, segment);
+					let child = childrenContainer[segment];
+					
+					let setParent = (
+						parentKey != null
+						&& child[parentKey] == null
+						&& (treatRootAsParent || i >= 1)
+					);
+
+					if (setParent) {
+						child[parentKey] = lastItem;
+					}
+					
+					if (i === path.length - 1) {
+						// Last segment, this is where we want to put the item data
+						child = childrenContainer[segment] = {
+							... item,
+							... child
+						};
+					}
+					
+					lastItem = child;
+				}
+			}
+		},
+		done: function () {
+			done = true;
+			return root;
+		}
+	};
+};
+
+// let builder = module.exports({ childrenKey: "children", parentKey: "parent" });
+// builder.add([], { description: "root" });
+// builder.add(["a"], { description: "root -> a" });
+// builder.add(["b", "c"], { description: "root -> b -> c" });
+// builder.add(["b"], { description: "root -> b" });
+// builder.add(["a", "c"], { description: "root -> a -> c" });
+// builder.add(["a", "c", "d"], { description: "root -> a -> c -> d" });
+// console.dir(builder.done(), { depth: null });
diff --git a/package.json b/package.json
index e0a248e..73f0782 100644
--- a/package.json
+++ b/package.json
@@ -5,9 +5,13 @@
   "description": "An IMAP module for node.js that makes communicating with IMAP servers easy",
   "main": "./lib/Connection",
   "dependencies": {
+    "@joepie91/unreachable": "^1.0.0",
+    "as-expression": "^1.0.0",
     "bluebird": "^3.7.2",
     "default-value": "^1.0.0",
+    "last-item": "^1.0.0",
     "map-obj": "^4.2.1",
+    "match-value": "^1.1.0",
     "p-defer": "^3.0.0",
     "p-try": "^2.2.0",
     "readable-stream": "1.1.x",
diff --git a/test/reference-tree.js b/test/reference-tree.js
new file mode 100644
index 0000000..c8e35cf
--- /dev/null
+++ b/test/reference-tree.js
@@ -0,0 +1,138 @@
+"use strict";
+
+// FIXME: Publish as stand-alone `reference-tree` package, clearly document that it is not order-sensitive
+
+function isObject(value) {
+	return (value != null && typeof value === "object");
+}
+
+function isLabelReference(value) {
+	return (isObject(value) && value.__referenceTree_reference != null);
+}
+
+function isParentReference(value) {
+	return (isObject(value) && value.__referenceTree_parent != null);
+}
+
+function hasLabel(value) {
+	return (isObject(value) && value.__referenceTree_label != null);
+}
+
+module.exports = {
+	build: function buildReferenceTree(object) {
+		// NOTE: Mutates input object!
+		let stack = [];
+		let labelledItems = new Map();
+		let seen = new Set();
+		let onFirstPass = true;
+		let doSecondPass = false;
+
+		function handleItem(container, key) {
+			let value = container[key];
+
+			if (!seen.has(value)) {
+				seen.add(value);
+
+				if (hasLabel(value)) {
+					let label = value.__referenceTree_label;
+					delete value.__referenceTree_label;
+
+					labelledItems.set(label, value);
+				}
+
+				if (isLabelReference(value)) {
+					let label = value.__referenceTree_reference;
+
+					if (labelledItems.has(label)) {
+						container[key] = labelledItems.get(label);
+					} else if (onFirstPass) {
+						// We haven't seen the referenced item yet; this typically happens when either the reference is defined before the label, or when there are cyclical references
+						doSecondPass = true;
+					} else {
+						throw new Error(`Encountered a label '${label}' that doesn't exist anywhere in the tree`);
+					}
+				} else if (isParentReference(value)) {
+					let levels = value.__referenceTree_parent;
+					
+					if (levels > stack.length) {
+						throw new Error(`Tried to access a parent ${levels} steps away, but there are only ${stack.length} parents`);
+					} else {
+						let parentIndex = stack.length - levels;
+						container[key] = stack[parentIndex];
+					}
+				} else {
+					stack.push(container);
+					processValue(value);
+					stack.pop();
+				}
+			}
+		}
+
+		function processObject(object) {
+			for (let key of Object.keys(object)) {
+				handleItem(object, key);
+			}
+		}
+
+		function processArray(array) {
+			for (let i = 0; i < array.length; i++) {
+				handleItem(array, i);
+			}
+		}
+
+		function processValue(value) {
+			if (Array.isArray(value)) {
+				return processArray(value);
+			} else if (isObject(value)) {
+				return processObject(value);
+			}
+		}
+
+		processValue(object);
+
+		if (doSecondPass === true) {
+			onFirstPass = false;
+			seen = new Set();
+			processValue(object);
+		}
+
+		return object;
+	},
+	Parent: function (levels = 1) {
+		return {
+			__referenceTree_parent: levels
+		};
+	},
+	Label: function (label, object) {
+		object.__referenceTree_label = label;
+		return object;
+	},
+	Reference: function (label) {
+		return {
+			__referenceTree_reference: label
+		};
+	}
+};
+
+// let { build, Label, Reference, Parent } = module.exports;
+
+// let result = build({
+// 	foo: "bar",
+// 	a: Label("A", {
+// 		letter: "A",
+// 		foo: Reference("B")
+// 	}),
+// 	b: Label("B", {
+// 		letter: "B",
+// 		foo: Reference("A"),
+// 		children: [{
+// 			qux: "quz"
+// 		}, {
+// 			qux: Parent(2),
+// 			quz: Reference("B")
+// 		}]
+// 	}),
+// });
+
+// console.dir(result, { depth: 4 });
+// console.log(result.b.children[1].qux === result.b.children[1].quz);
diff --git a/test/tests/box-tree.js b/test/tests/box-tree.js
new file mode 100644
index 0000000..28a376b
--- /dev/null
+++ b/test/tests/box-tree.js
@@ -0,0 +1,313 @@
+"use strict";
+
+const tap = require("tap");
+const { build, Parent } = require("../reference-tree");
+
+const createBoxTreeBuilder = require("../../lib/util/box-tree-builder");
+
+let input = [{
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'confirmed-spam'
+}, {
+	flags: ['\\HasNoChildren', '\\Trash'],
+	delimiter: '/',
+	name: 'Trash'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'SpamLikely'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'Spam'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'Sent Items'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'Archive'
+}, {
+	flags: ['\\HasNoChildren', '\\Drafts'],
+	delimiter: '/',
+	name: 'Drafts'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'Notes'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'TeamViewer'
+}, {
+	flags: ['\\HasNoChildren', '\\Sent'],
+	delimiter: '/',
+	name: 'Sent Messages'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'confirmed-ham'
+}, {
+	flags: ['\\Noselect', '\\HasChildren'],
+	delimiter: '/',
+	name: 'Public'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'Public/office3'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'Public/office4'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'Public/support'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'Public/root'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'Public/updates'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'Public/postmaster'
+}, {
+	flags: ['\\Noselect', '\\HasChildren'],
+	delimiter: '/',
+	name: 'Shared'
+}, {
+	flags: ['\\Noselect', '\\HasChildren'],
+	delimiter: '/',
+	name: 'Shared/d.marteva'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'Shared/d.marteva/INBOX'
+}, {
+	flags: ['\\HasNoChildren'],
+	delimiter: '/',
+	name: 'INBOX'
+}];
+
+let expected = build({
+	'confirmed-spam': {
+		name: "confirmed-spam",
+		path: [ "confirmed-spam" ],
+		attributes: ['\\HasNoChildren'],
+		delimiter: '/',
+		children: null,
+		parent: null,
+		specialUseAttribute: undefined
+	},
+	Trash: {
+		name: "Trash",
+		path: [ "Trash" ],
+		attributes: ['\\HasNoChildren', '\\Trash'],
+		delimiter: '/',
+		children: null,
+		parent: null,
+		specialUseAttribute: '\\Trash'
+	},
+	SpamLikely: {
+		name: "SpamLikely",
+		path: [ "SpamLikely" ],
+		attributes: ['\\HasNoChildren'],
+		delimiter: '/',
+		children: null,
+		parent: null,
+		specialUseAttribute: undefined
+	},
+	Spam: {
+		name: "Spam",
+		path: [ "Spam" ],
+		attributes: ['\\HasNoChildren'],
+		delimiter: '/',
+		children: null,
+		parent: null,
+		specialUseAttribute: undefined
+	},
+	'Sent Items': {
+		name: "Sent Items",
+		path: [ "Sent Items" ],
+		attributes: ['\\HasNoChildren'],
+		delimiter: '/',
+		children: null,
+		parent: null,
+		specialUseAttribute: undefined
+	},
+	Archive: {
+		name: "Archive",
+		path: [ "Archive" ],
+		attributes: ['\\HasNoChildren'],
+		delimiter: '/',
+		children: null,
+		parent: null,
+		specialUseAttribute: undefined
+	},
+	Drafts: {
+		name: "Drafts",
+		path: [ "Drafts" ],
+		attributes: ['\\HasNoChildren', '\\Drafts'],
+		delimiter: '/',
+		children: null,
+		parent: null,
+		specialUseAttribute: '\\Drafts'
+	},
+	Notes: {
+		name: "Notes",
+		path: [ "Notes" ],
+		attributes: ['\\HasNoChildren'],
+		delimiter: '/',
+		children: null,
+		parent: null,
+		specialUseAttribute: undefined
+	},
+	TeamViewer: {
+		name: "TeamViewer",
+		path: [ "TeamViewer" ],
+		attributes: ['\\HasNoChildren'],
+		delimiter: '/',
+		children: null,
+		parent: null,
+		specialUseAttribute: undefined
+	},
+	'Sent Messages': {
+		name: "Sent Messages",
+		path: [ "Sent Messages" ],
+		attributes: ['\\HasNoChildren', '\\Sent'],
+		delimiter: '/',
+		children: null,
+		parent: null,
+		specialUseAttribute: '\\Sent'
+	},
+	'confirmed-ham': {
+		name: "confirmed-ham",
+		path: [ "confirmed-ham" ],
+		attributes: ['\\HasNoChildren'],
+		delimiter: '/',
+		children: null,
+		parent: null,
+		specialUseAttribute: undefined
+	},
+	Public: {
+		name: "Public",
+		path: [ "Public" ],
+		attributes: ['\\Noselect', '\\HasChildren'],
+		delimiter: '/',
+		children: {
+			office3: {
+				name: "office3",
+				path: [ "Public", "office3" ],
+				attributes: ['\\HasNoChildren'],
+				delimiter: '/',
+				children: null,
+				parent: Parent(2),
+				specialUseAttribute: undefined
+			},
+			office4: {
+				name: "office4",
+				path: [ "Public", "office4" ],
+				attributes: ['\\HasNoChildren'],
+				delimiter: '/',
+				children: null,
+				parent: Parent(2),
+				specialUseAttribute: undefined
+			},
+			support: {
+				name: "support",
+				path: [ "Public", "support" ],
+				attributes: ['\\HasNoChildren'],
+				delimiter: '/',
+				children: null,
+				parent: Parent(2),
+				specialUseAttribute: undefined
+			},
+			root: {
+				name: "root",
+				path: [ "Public", "root" ],
+				attributes: ['\\HasNoChildren'],
+				delimiter: '/',
+				children: null,
+				parent: Parent(2),
+				specialUseAttribute: undefined
+			},
+			updates: {
+				name: "updates",
+				path: [ "Public", "updates" ],
+				attributes: ['\\HasNoChildren'],
+				delimiter: '/',
+				children: null,
+				parent: Parent(2),
+				specialUseAttribute: undefined
+			},
+			postmaster: {
+				name: "postmaster",
+				path: [ "Public", "postmaster" ],
+				attributes: ['\\HasNoChildren'],
+				delimiter: '/',
+				children: null,
+				parent: Parent(2),
+				specialUseAttribute: undefined
+			}
+		},
+		parent: null,
+		specialUseAttribute: undefined
+	},
+	Shared: {
+		name: "Shared",
+		path: [ "Shared" ],
+		attributes: ['\\Noselect', '\\HasChildren'],
+		delimiter: '/',
+		children: {
+			'd.marteva': {
+				name: "d.marteva",
+				path: [ "Shared", "d.marteva" ],
+				attributes: ['\\Noselect', '\\HasChildren'],
+				delimiter: '/',
+				children: {
+					INBOX: {
+						name: "INBOX",
+						path: [ "Shared", "d.marteva", "INBOX" ],
+						attributes: ['\\HasNoChildren'],
+						delimiter: '/',
+						children: null,
+						parent: Parent(2),
+						specialUseAttribute: undefined
+					}
+				},
+				parent: Parent(2),
+				specialUseAttribute: undefined
+			}
+		},
+		parent: null,
+		specialUseAttribute: undefined
+	},
+	INBOX: {
+		name: "INBOX",
+		path: [ "INBOX" ],
+		attributes: ['\\HasNoChildren'],
+		delimiter: '/',
+		children: null,
+		parent: null,
+		specialUseAttribute: undefined
+	}
+});
+
+tap.test("build-box-tree", (test) => {
+	let builder = createBoxTreeBuilder();
+	
+	for (let item of input) {
+		builder.add(item);
+	}
+
+	test.same(builder.done(), expected);
+
+	// Needed to convince node-tap that the test is completed, for some reason...
+	return Promise.resolve();
+});
diff --git a/test/tests/list.js b/test/tests/list.js
new file mode 100644
index 0000000..bbd4db9
--- /dev/null
+++ b/test/tests/list.js
@@ -0,0 +1,111 @@
+"use strict";
+
+const Promise = require("bluebird");
+const tap = require("tap");
+const pEvent = require("p-event");
+const IMAP = require("../../lib/Connection");
+
+const lines = require("../lines");
+const createMockServer = require("../mock-server");
+
+tap.test("list", (test) => {
+	return testFetch(test);
+});
+
+function testFetch(test) {
+	let steps = [{
+		expected: 'A0 CAPABILITY',
+		response: lines([
+			'* CAPABILITY IMAP4rev1 UNSELECT IDLE NAMESPACE QUOTA CHILDREN',
+			'A0 OK Thats all she wrote!',
+		]),
+	}, {
+		expected: 'A1 LOGIN "foo" "bar"',
+		response: lines([
+			'* CAPABILITY IMAP4rev1 UNSELECT IDLE NAMESPACE QUOTA CHILDREN UIDPLUS MOVE',
+			'A1 OK authenticated (Success)',
+		]),
+	}, {
+		expected: 'A2 NAMESPACE',
+		response: lines([
+			'* NAMESPACE (("" "/")) NIL NIL',
+			'A2 OK Success',
+		]),
+	}, {
+		expected: 'A3 LIST "" ""',
+		response: lines([
+			'* LIST (\\HasNoChildren) "/" confirmed-spam',
+			'* LIST (\\HasNoChildren \\Trash) "/" Trash',
+			'* LIST (\\HasNoChildren) "/" SpamLikely',
+			'* LIST (\\HasNoChildren) "/" Spam',
+			'* LIST (\\HasNoChildren) "/" "Sent Items"',
+			'* LIST (\\HasNoChildren) "/" Archive',
+			'* LIST (\\HasNoChildren \\Drafts) "/" Drafts',
+			'* LIST (\\HasNoChildren) "/" Notes',
+			'* LIST (\\HasNoChildren) "/" TeamViewer',
+			'* LIST (\\HasNoChildren \\Sent) "/" "Sent Messages"',
+			'* LIST (\\HasNoChildren) "/" confirmed-ham',
+			'* LIST (\\Noselect \\HasChildren) "/" Public',
+			'* LIST (\\HasNoChildren) "/" Public/office3',
+			'* LIST (\\HasNoChildren) "/" Public/office4',
+			'* LIST (\\HasNoChildren) "/" Public/support',
+			'* LIST (\\HasNoChildren) "/" Public/root',
+			'* LIST (\\HasNoChildren) "/" Public/updates',
+			'* LIST (\\HasNoChildren) "/" Public/postmaster',
+			'* LIST (\\Noselect \\HasChildren) "/" Shared',
+			'* LIST (\\Noselect \\HasChildren) "/" Shared/d.marteva',
+			'* LIST (\\HasNoChildren) "/" Shared/d.marteva/INBOX',
+			'* LIST (\\HasNoChildren) "/" INBOX',
+			'A3 OK Success',
+		]),
+	}, {
+		expected: 'A4 EXAMINE "INBOX"',
+		response: lines([
+			'* FLAGS (\\Answered \\Flagged \\Draft \\Deleted \\Seen)',
+			'* OK [PERMANENTFLAGS ()] Flags permitted.',
+			'* OK [UIDVALIDITY 2] UIDs valid.',
+			'* 685 EXISTS',
+			'* 0 RECENT',
+			'* OK [UIDNEXT 4422] Predicted next UID.',
+			'A4 OK [READ-ONLY] INBOX selected. (Success)',
+		]),
+	}, {
+		expected: "A5 LOGOUT",
+		response: lines([
+			'* BYE LOGOUT Requested',
+			'A5 OK good day (Success)',
+		]),
+	}];
+	
+	return Promise.try(() => {
+		return createMockServer({
+			steps: steps,
+			test: test
+		});
+	}).then(({ server, port, finalize }) => {
+		const client = new IMAP({
+			user: "foo",
+			password: "bar",
+			host: "127.0.0.1",
+			port: port,
+			keepalive: false
+		});
+	
+		Promise.promisifyAll(client, { multiArgs: true });
+		client.connect();
+		
+		return Promise.try(() => {
+			return pEvent(client, "ready");
+		}).then(() => {
+			server.close(); // Stop listening for new clients
+	
+			return client.openBoxAsync("INBOX", true);
+		}).tap(() => {
+			client.end();
+
+			return pEvent(client, "end");
+		}).then(() => {
+			finalize();
+		});
+	});
+}
diff --git a/yarn.lock b/yarn.lock
index 48ebbb4..164f1c0 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -321,6 +321,11 @@
   resolved "https://registry.yarnpkg.com/@joepie91/eslint-config/-/eslint-config-1.1.0.tgz#9397e6ce0a010cb57dcf8aef8754d3a5ce0ae36a"
   integrity sha512-XliasRSUfOz1/bAvTBaUlCjWDbceCW4y1DnvFfW7Yw9p2FbNRR0w8WoPdTxTCjKuoZ7/OQMeBxIe2y9Qy6rbYw==
 
+"@joepie91/unreachable@^1.0.0":
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/@joepie91/unreachable/-/unreachable-1.0.0.tgz#8032bb8a5813e81bbbe516cb3031d60818526687"
+  integrity sha512-vZRJ5UDq4mqP1vgSrcOLD3aIfS/nzwsvGFOOHv5sj5fa1Ss0dT1xnIzrXKLD9pu5EcUvF3K6n6jdaMW8uXpNEQ==
+
 "@types/prop-types@*":
   version "15.7.4"
   resolved "https://registry.yarnpkg.com/@types/prop-types/-/prop-types-15.7.4.tgz#fcf7205c25dff795ee79af1e30da2c9790808f11"
@@ -471,6 +476,11 @@ arrify@^2.0.1:
   resolved "https://registry.yarnpkg.com/arrify/-/arrify-2.0.1.tgz#c9655e9331e0abcd588d2a7cad7e9956f66701fa"
   integrity sha512-3duEwti880xqi4eAMN8AyR4a0ByT90zoYdLlevfrvU43vb0YZwZVfxOgxWrLXXXpyugL0hNZc9G6BiB5B3nUug==
 
+as-expression@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/as-expression/-/as-expression-1.0.0.tgz#7bc620ca4cb2fe0ee90d86729bd6add33b8fd831"
+  integrity sha512-Iqh4GxNUfxbJdGn6b7/XMzc8m1Dz2ZHouBQ9DDTzyMRO3VPPIAXeoY/sucRxxxXKbUtzwzWZSN6jPR3zfpYHHA==
+
 asn1@~0.2.3:
   version "0.2.4"
   resolved "https://registry.yarnpkg.com/asn1/-/asn1-0.2.4.tgz#8d2475dfab553bb33e77b54e59e880bb8ce23136"
@@ -1628,6 +1638,11 @@ jsprim@^1.2.2:
     json-schema "0.2.3"
     verror "1.10.0"
 
+last-item@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/last-item/-/last-item-1.0.0.tgz#54e5fbb09e46f5ebcb3b334e1ca0e015fbda633b"
+  integrity sha512-1F6OpdMLea5/489SjQj2UVP4cXb9qpMxuUU4xHpUH86PnhGldKf7oDtu8hy7a+3GCdvikEFtP4y5PoPsYVnC6g==
+
 lcov-parse@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/lcov-parse/-/lcov-parse-1.0.0.tgz#eb0d46b54111ebc561acb4c408ef9363bdc8f7e0"
@@ -1723,6 +1738,11 @@ map-obj@^4.2.1:
   resolved "https://registry.yarnpkg.com/map-obj/-/map-obj-4.2.1.tgz#e4ea399dbc979ae735c83c863dd31bdf364277b7"
   integrity sha512-+WA2/1sPmDj1dlvvJmB5G6JKfY9dpn7EVBUL06+y6PoljPkh+6V1QihwxNkbcGxCRjt2b0F9K0taiCuo7MbdFQ==
 
+match-value@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/match-value/-/match-value-1.1.0.tgz#ad311ef8bbe2d344a53ec3104e28fe221984b98e"
+  integrity sha512-NOvpobcmkX+l9Eb6r2s3BkR1g1ZwzExDFdXA9d6p1r1O1olLbo88KuzMiBmg43xSpodfm7I6Hqlx2OoySquEgg==
+
 mime-db@1.48.0:
   version "1.48.0"
   resolved "https://registry.yarnpkg.com/mime-db/-/mime-db-1.48.0.tgz#e35b31045dd7eada3aaad537ed88a33afbef2d1d"