diff --git a/src/controllers/molecules/MessageComposer.js b/src/controllers/molecules/MessageComposer.js
index f55546ae87..c2b67c7898 100644
--- a/src/controllers/molecules/MessageComposer.js
+++ b/src/controllers/molecules/MessageComposer.js
@@ -14,19 +14,130 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-'use strict';
-
 var MatrixClientPeg = require("../../MatrixClientPeg");
+var SlashCommands = require("../../SlashCommands");
+var Modal = require("../../Modal");
+var sdk = require('../../index');
 
 var dis = require("../../dispatcher");
+var KeyCode = {
+    ENTER: 13,
+    TAB: 9,
+    SHIFT: 16,
+    UP: 38,
+    DOWN: 40
+};
+
+var TYPING_USER_TIMEOUT = 10000;
+var TYPING_SERVER_TIMEOUT = 30000;
 
 module.exports = {
+    componentWillMount: function() {
+        this.tabStruct = {
+            completing: false,
+            original: null,
+            index: 0
+        };
+        this.sentHistory = {
+            // The list of typed messages. Index 0 is more recent
+            data: [],
+            // The position in data currently displayed
+            position: -1,
+            // The room the history is for.
+            roomId: null,
+            // The original text before they hit UP
+            originalText: null,
+            // The textarea element to set text to.
+            element: null,
+
+            init: function(element, roomId) {
+                this.roomId = roomId;
+                this.element = element;
+                this.position = -1;
+                var storedData = window.sessionStorage.getItem(
+                    "history_" + roomId
+                );
+                if (storedData) {
+                    this.data = JSON.parse(storedData);
+                }
+                if (this.roomId) {
+                    this.setLastTextEntry();
+                }
+            },
+
+            push: function(text) {
+                // store a message in the sent history
+                this.data.unshift(text);
+                window.sessionStorage.setItem(
+                    "history_" + this.roomId,
+                    JSON.stringify(this.data)
+                );
+                // reset history position
+                this.position = -1;
+                this.originalText = null;
+            },
+
+            // move in the history. Returns true if we managed to move.
+            next: function(offset) {
+                if (this.position === -1) {
+                    // user is going into the history, save the current line.
+                    this.originalText = this.element.value;
+                }
+                else {
+                    // user may have modified this line in the history; remember it.
+                    this.data[this.position] = this.element.value;
+                }
+
+                if (offset > 0 && this.position === (this.data.length - 1)) {
+                    // we've run out of history
+                    return false;
+                }
+
+                // retrieve the next item (bounded).
+                var newPosition = this.position + offset;
+                newPosition = Math.max(-1, newPosition);
+                newPosition = Math.min(newPosition, this.data.length - 1);
+                this.position = newPosition;
+
+                if (this.position !== -1) {
+                    // show the message
+                    this.element.value = this.data[this.position];
+                }
+                else if (this.originalText !== undefined) {
+                    // restore the original text the user was typing.
+                    this.element.value = this.originalText;
+                }
+                return true;
+            },
+
+            saveLastTextEntry: function() {
+                // save the currently entered text in order to restore it later.
+                // NB: This isn't 'originalText' because we want to restore
+                // sent history items too!
+                var text = this.element.value;
+                window.sessionStorage.setItem("input_" + this.roomId, text);
+            },
+
+            setLastTextEntry: function() {
+                var text = window.sessionStorage.getItem("input_" + this.roomId);
+                if (text) {
+                    this.element.value = text;
+                }
+            }
+        };
+    },
+
     componentDidMount: function() {
         this.dispatcherRef = dis.register(this.onAction);
+        this.sentHistory.init(
+            this.refs.textarea.getDOMNode(),
+            this.props.room.roomId
+        );
     },
 
     componentWillUnmount: function() {
         dis.unregister(this.dispatcherRef);
+        this.sentHistory.saveLastTextEntry();
     },
 
     onAction: function(payload) {
@@ -38,30 +149,265 @@ module.exports = {
     },
 
     onKeyDown: function (ev) {
-        if (ev.keyCode == 13) {
-            var contentText = this.refs.textarea.getDOMNode().value;
-
-            var content = null;
-            if (/^\/me /i.test(contentText)) {
-                content = {
-                    msgtype: 'm.emote',
-                    body: contentText.substring(4)
-                };
-            } else {
-                content = {
-                    msgtype: 'm.text',
-                    body: contentText
-                };
+        if (ev.keyCode === KeyCode.ENTER) {
+            var input = this.refs.textarea.getDOMNode().value;
+            if (input.length === 0) {
+                ev.preventDefault();
+                return;
             }
-
-            MatrixClientPeg.get().sendMessage(this.props.roomId, content).then(function() {
-                dis.dispatch({
-                    action: 'message_sent'
-                });
-            });
-            this.refs.textarea.getDOMNode().value = '';
+            this.sentHistory.push(input);
+            this.onEnter(ev);
+        }
+        else if (ev.keyCode === KeyCode.TAB) {
+            var members = [];
+            if (this.props.room) {
+                members = this.props.room.getJoinedMembers();
+            }
+            this.onTab(ev, members);
+        }
+        else if (ev.keyCode === KeyCode.UP || ev.keyCode === KeyCode.DOWN) {
+            this.sentHistory.next(
+                ev.keyCode === KeyCode.UP ? 1 : -1
+            );
             ev.preventDefault();
         }
+        else if (ev.keyCode !== KeyCode.SHIFT && this.tabStruct.completing) {
+            // they're resuming typing; reset tab complete state vars.
+            this.tabStruct.completing = false;
+            this.tabStruct.index = 0;
+        }
+
+        var self = this;
+        setTimeout(function() {
+            if (self.refs.textarea && self.refs.textarea.getDOMNode().value != '') {
+                self.onTypingActivity();
+            } else {
+                self.onFinishedTyping();
+            }
+        }, 10); // XXX: what is this 10ms setTimeout doing?  Looks hacky :(
     },
+
+    onEnter: function(ev) {
+        var contentText = this.refs.textarea.getDOMNode().value;
+
+        var cmd = SlashCommands.processInput(this.props.room.roomId, contentText);
+        if (cmd) {
+            ev.preventDefault();
+            if (!cmd.error) {
+                this.refs.textarea.getDOMNode().value = '';
+            }
+            if (cmd.promise) {
+                cmd.promise.done(function() {
+                    console.log("Command success.");
+                }, function(err) {
+                    console.error("Command failure: %s", err);
+                    var ErrorDialog = sdk.getComponent("organisms.ErrorDialog");
+                    Modal.createDialog(ErrorDialog, {
+                        title: "Server error",
+                        description: err.message
+                    });
+                });
+            }
+            else if (cmd.error) {
+                console.error(cmd.error);
+                var ErrorDialog = sdk.getComponent("organisms.ErrorDialog");
+                Modal.createDialog(ErrorDialog, {
+                    title: "Command error",
+                    description: cmd.error
+                });
+            }
+            return;
+        }
+
+        var content = null;
+        if (/^\/me /i.test(contentText)) {
+            content = {
+                msgtype: 'm.emote',
+                body: contentText.substring(4)
+            };
+        } else {
+            content = {
+                msgtype: 'm.text',
+                body: contentText
+            };
+        }
+
+        MatrixClientPeg.get().sendMessage(this.props.room.roomId, content).then(function() {
+            dis.dispatch({
+                action: 'message_sent'
+            });
+        }, function() {
+            dis.dispatch({
+                action: 'message_send_failed'
+            });
+        });
+        this.refs.textarea.getDOMNode().value = '';
+        ev.preventDefault();
+    },
+
+    onTab: function(ev, sortedMembers) {
+        var textArea = this.refs.textarea.getDOMNode();
+        if (!this.tabStruct.completing) {
+            this.tabStruct.completing = true;
+            this.tabStruct.index = 0;
+            // cache starting text
+            this.tabStruct.original = textArea.value;
+        }
+
+        // loop in the right direction
+        if (ev.shiftKey) {
+            this.tabStruct.index --;
+            if (this.tabStruct.index < 0) {
+                // wrap to the last search match, and fix up to a real index
+                // value after we've matched.
+                this.tabStruct.index = Number.MAX_VALUE;
+            }
+        }
+        else {
+            this.tabStruct.index++;
+        }
+
+        var searchIndex = 0;
+        var targetIndex = this.tabStruct.index;
+        var text = this.tabStruct.original;
+
+        var search = /@?([a-zA-Z0-9_\-:\.]+)$/.exec(text);
+        // console.log("Searched in '%s' - got %s", text, search);
+        if (targetIndex === 0) { // 0 is always the original text
+            textArea.value = text;
+        }
+        else if (search && search[1]) {
+            // console.log("search found: " + search+" from "+text);
+            var expansion;
+
+            // FIXME: could do better than linear search here
+            for (var i=0; i<sortedMembers.length; i++) {
+                var member = sortedMembers[i];
+                if (member.name && searchIndex < targetIndex) {
+                    if (member.name.toLowerCase().indexOf(search[1].toLowerCase()) === 0) {
+                        expansion = member.name;
+                        searchIndex++;
+                    }
+                }
+            }
+
+            if (searchIndex < targetIndex) { // then search raw mxids
+                for (var i=0; i<sortedMembers.length; i++) {
+                    if (searchIndex >= targetIndex) {
+                        break;
+                    }
+                    var userId = sortedMembers[i].userId;
+                    // === 1 because mxids are @username
+                    if (userId.toLowerCase().indexOf(search[1].toLowerCase()) === 1) {
+                        expansion = userId;
+                        searchIndex++;
+                    }
+                }
+            }
+
+            if (searchIndex === targetIndex ||
+                    targetIndex === Number.MAX_VALUE) {
+                // xchat-style tab complete, add a colon if tab
+                // completing at the start of the text
+                if (search[0].length === text.length) {
+                    expansion += ": ";
+                }
+                else {
+                    expansion += " ";
+                }
+                textArea.value = text.replace(
+                    /@?([a-zA-Z0-9_\-:\.]+)$/, expansion
+                );
+                // cancel blink
+                textArea.style["background-color"] = "";
+                if (targetIndex === Number.MAX_VALUE) {
+                    // wrap the index around to the last index found
+                    this.tabStruct.index = searchIndex;
+                    targetIndex = searchIndex;
+                }
+            }
+            else {
+                // console.log("wrapped!");
+                textArea.style["background-color"] = "#faa";
+                setTimeout(function() {
+                     textArea.style["background-color"] = "";
+                }, 150);
+                textArea.value = text;
+                this.tabStruct.index = 0;
+            }
+        }
+        else {
+            this.tabStruct.index = 0;
+        }
+        // prevent the default TAB operation (typically focus shifting)
+        ev.preventDefault();
+    },
+
+    onTypingActivity: function() {
+        this.isTyping = true;
+        if (!this.userTypingTimer) {
+            this.sendTyping(true);
+        }
+        this.startUserTypingTimer();
+        this.startServerTypingTimer();
+    },
+
+    onFinishedTyping: function() {
+        this.isTyping = false;
+        this.sendTyping(false);
+        this.stopUserTypingTimer();
+        this.stopServerTypingTimer();
+    },
+
+    startUserTypingTimer: function() {
+        this.stopUserTypingTimer();
+        var self = this;
+        this.userTypingTimer = setTimeout(function() {
+            self.isTyping = false;
+            self.sendTyping(self.isTyping);
+            self.userTypingTimer = null;
+        }, TYPING_USER_TIMEOUT);
+    },
+
+    stopUserTypingTimer: function() {
+        if (this.userTypingTimer) {
+            clearTimeout(this.userTypingTimer);
+            this.userTypingTimer = null;
+        }
+    },
+
+    startServerTypingTimer: function() {
+        if (!this.serverTypingTimer) {
+            var self = this;
+            this.serverTypingTimer = setTimeout(function() {
+                if (self.isTyping) {
+                    self.sendTyping(self.isTyping);
+                    self.startServerTypingTimer();
+                }
+            }, TYPING_SERVER_TIMEOUT / 2);
+        }
+    },
+
+    stopServerTypingTimer: function() {
+        if (this.serverTypingTimer) {
+            clearTimeout(this.servrTypingTimer);
+            this.serverTypingTimer = null;
+        }
+    },
+
+    sendTyping: function(isTyping) {
+        MatrixClientPeg.get().sendTyping(
+            this.props.room.roomId,
+            this.isTyping, TYPING_SERVER_TIMEOUT
+        ).done();
+    },
+
+    refreshTyping: function() {
+        if (this.typingTimeout) {
+            clearTimeout(this.typingTimeout);
+            this.typingTimeout = null;
+        }
+
+    }
 };