diff --git a/lib/todo-app.js b/lib/todo-app.js
index 2b9c956..2a4511c 100644
--- a/lib/todo-app.js
+++ b/lib/todo-app.js
@@ -5,10 +5,25 @@ if (typeof require !== 'undefined' && this.window !== this) {
     route, section, span, strong, text, ul } = require('./elmish.js');
 }
 
-var initial_model = {
+function set_search_state(model, value) {
+  Object.defineProperty(model, 'search', {
+    value: value || '',
+    writable: true,
+    configurable: true,
+    enumerable: false
+  });
+  return model;
+}
+
+function clone_model(model) {
+  var cloned = JSON.parse(JSON.stringify(model));
+  return set_search_state(cloned, model && model.search);
+}
+
+var initial_model = set_search_state({
   todos: [],
   hash: "#/"
-}
+}, "")
 
 /**
  * `update` transforms the `model` based on the `action`.
@@ -18,7 +33,7 @@ var initial_model = {
  * @return {Object} new_model - the transformed model.
  */
 function update(action, model, data) {
-  var new_model = JSON.parse(JSON.stringify(model)) // "clone" the model
+  var new_model = clone_model(model) // "clone" the model
 
   switch(action) {
     case 'ADD':
@@ -103,6 +118,9 @@ function update(action, model, data) {
       new_model.hash = // (window && window.location && window.location.hash) ?
         window.location.hash // : '#/';
       break;
+    case 'SEARCH':
+      set_search_state(new_model, data);
+      break;
     default: // if action unrecognised or undefined,
       return model; // return model unmodified
   }   // see: https://softwareengineering.stackexchange.com/a/201786/211301
@@ -162,36 +180,49 @@ function render_item (item, model, signal) {
  * @return {Object} <section> DOM Tree which containing the todo list <ul>, etc.
  */
 function render_main (model, signal) {
-  // Requirement #1 - No Todos, should hide #footer and #main
-  var display = "style=display:"
-    + (model.todos && model.todos.length > 0 ? "block" : "none");
+  var has_todos = model.todos && model.todos.length > 0;
+  var display = "style=display:" + (has_todos ? "block" : "none");
+
+  var filtered_by_route = has_todos ? model.todos.filter(function (item) {
+    switch(model.hash) {
+      case '#/active':
+        return !item.done;
+      case '#/completed':
+        return item.done;
+      default:
+        return item;
+    }
+  }) : [];
+
+  var search_term = (model.search || '').trim();
+  var filtered_items = filtered_by_route;
+
+  if (search_term.length > 0) {
+    filtered_items = filtered_by_route.filter(function (item) {
+      return item.title.toLowerCase().indexOf(search_term.toLowerCase()) !== -1;
+    });
+  }
+
+  var has_filtered_items = filtered_items.length > 0;
+  var show_empty_message = has_todos && !has_filtered_items;
 
   return (
-    section(["class=main", "id=main", display], [ // hide if no todo items.
+    section(["class=main", "id=main", display], [
       input(["id=toggle-all", "type=checkbox",
         typeof signal === 'function' ? signal('TOGGLE_ALL') : '',
         (model.all_done ? "checked=checked" : ""),
         "class=toggle-all"
       ], []),
       label(["for=toggle-all"], [ text("Mark all as complete") ]),
-      ul(["class=todo-list"],
-        (model.todos && model.todos.length > 0) ?
-        model.todos
-        .filter(function (item) {
-          switch(model.hash) {
-            case '#/active':
-              return !item.done;
-            case '#/completed':
-              return item.done;
-            default: // if hash doesn't match Active/Completed render ALL todos:
-              return item;
-          }
-        })
-        .map(function (item) {
-          return render_item(item, model, signal)
-        }) : null
-      ) // </ul>
-    ]) // </section>
+      show_empty_message ?
+        div(["class=empty-message"], [text("No todos match your search.")]) :
+        ul(["class=todo-list"],
+          has_filtered_items ?
+          filtered_items.map(function (item) {
+            return render_item(item, model, signal)
+          }) : null
+        )
+    ])
   )
 }
 
@@ -281,6 +312,7 @@ function render_footer (model, signal) {
  * var DOM = view(model);
  */
 function view (model, signal) {
+  var search_value = model.search || '';
 
   return (
     section(["class=todoapp"], [ // array of "child" elements
@@ -293,7 +325,13 @@ function view (model, signal) {
           "class=new-todo",
           "placeholder=What needs to be done?",
           "autofocus"
-        ], []) // <input> is "self-closing"
+        ], []), // <input> is "self-closing"
+        input([
+          "id=search-todo",
+          "class=search-todo",
+          "placeholder=Search todos...",
+          "value=" + search_value
+        ], []) // search input
       ]), // </header>
       render_main(model, signal),
       render_footer(model, signal)
@@ -311,6 +349,8 @@ function subscriptions (signal) {
 	var ENTER_KEY = 13; // add a new todo item when [Enter] key is pressed
 	var ESCAPE_KEY = 27; // used for "escaping" when editing a Todo item
 
+  signal('SEARCH', '')();
+
   document.addEventListener('keyup', function handler (e) {
     // console.log('e.keyCode:', e.keyCode, '| key:', e.key);
 
@@ -337,6 +377,12 @@ function subscriptions (signal) {
   window.onhashchange = function route () {
     signal('ROUTE')();
   }
+
+  document.addEventListener('input', function (e) {
+    if (e.target && e.target.id === 'search-todo') {
+      signal('SEARCH', e.target.value)();
+    }
+  });
 }
 
 /* module.exports is needed to run the functions using Node.js for testing! */
diff --git a/test/todo-app.test.js b/test/todo-app.test.js
index 5ec459c..57d7d42 100644
--- a/test/todo-app.test.js
+++ b/test/todo-app.test.js
@@ -678,3 +678,149 @@ test('9. Routing > should allow me to display active/completed/all items',
   t.end();
 });
 
+test('10. Search > should filter todos by search term', function (t) {
+  localStorage.removeItem('todos-elmish_' + id);
+  elmish.empty(document.getElementById(id));
+  const model = {
+    todos: [
+      { id: 0, title: "Buy milk", done: false },
+      { id: 1, title: "Buy eggs", done: false },
+      { id: 2, title: "Walk the dog", done: true }
+    ],
+    hash: '#/'
+  };
+  elmish.mount(model, app.update, app.view, id, app.subscriptions);
+
+  t.equal(document.querySelectorAll('.view').length, 3, "three items total");
+
+  const model_with_search = app.update('SEARCH', model, 'milk');
+  elmish.empty(document.getElementById(id));
+  document.getElementById(id).appendChild(app.render_main(model_with_search, mock_signal));
+
+  t.equal(document.querySelectorAll('.view').length, 1, "one item matches 'milk'");
+  t.equal(document.querySelectorAll('.view')[0].textContent, 'Buy milk', "matching item is 'Buy milk'");
+
+  elmish.empty(document.getElementById(id));
+  localStorage.removeItem('todos-elmish_' + id);
+  t.end();
+});
+
+test('10.1 Search > should ignore leading and trailing whitespace in search term', function (t) {
+  localStorage.removeItem('todos-elmish_' + id);
+  elmish.empty(document.getElementById(id));
+  const model = {
+    todos: [
+      { id: 0, title: "Buy milk", done: false },
+      { id: 1, title: "Buy eggs", done: false }
+    ],
+    hash: '#/'
+  };
+
+  const model_with_whitespace = app.update('SEARCH', model, '  milk  ');
+  document.getElementById(id).appendChild(app.render_main(model_with_whitespace, mock_signal));
+
+  t.equal(document.querySelectorAll('.view').length, 1, "one item matches '  milk  ' (trimmed)");
+  t.equal(document.querySelectorAll('.view')[0].textContent, 'Buy milk', "matching item is 'Buy milk'");
+
+  elmish.empty(document.getElementById(id));
+
+  const model_with_only_spaces = app.update('SEARCH', model, '   ');
+  document.getElementById(id).appendChild(app.render_main(model_with_only_spaces, mock_signal));
+
+  t.equal(document.querySelectorAll('.view').length, 2, "all items shown when search term is only spaces");
+
+  elmish.empty(document.getElementById(id));
+  localStorage.removeItem('todos-elmish_' + id);
+  t.end();
+});
+
+test('10.2 Search > should show empty message when no items match search', function (t) {
+  localStorage.removeItem('todos-elmish_' + id);
+  elmish.empty(document.getElementById(id));
+  const model = {
+    todos: [
+      { id: 0, title: "Buy milk", done: false },
+      { id: 1, title: "Buy eggs", done: false }
+    ],
+    hash: '#/'
+  };
+
+  const model_with_search = app.update('SEARCH', model, 'nonexistent');
+  document.getElementById(id).appendChild(app.render_main(model_with_search, mock_signal));
+
+  t.equal(document.querySelectorAll('.view').length, 0, "no items match 'nonexistent'");
+  t.equal(document.querySelectorAll('.empty-message').length, 1, "empty message is shown");
+  t.equal(document.querySelectorAll('.empty-message')[0].textContent, 'No todos match your search.', "empty message text is correct");
+
+  elmish.empty(document.getElementById(id));
+  localStorage.removeItem('todos-elmish_' + id);
+  t.end();
+});
+
+test('10.3 Search > should not show empty message when there are no todos at all', function (t) {
+  localStorage.removeItem('todos-elmish_' + id);
+  elmish.empty(document.getElementById(id));
+  const model = {
+    todos: [],
+    hash: '#/'
+  };
+
+  const model_with_search = app.update('SEARCH', model, 'milk');
+  document.getElementById(id).appendChild(app.render_main(model_with_search, mock_signal));
+
+  t.equal(document.querySelectorAll('.empty-message').length, 0, "no empty message when there are no todos");
+
+  elmish.empty(document.getElementById(id));
+  localStorage.removeItem('todos-elmish_' + id);
+  t.end();
+});
+
+test('10.4 Search > should combine with route filter', function (t) {
+  localStorage.removeItem('todos-elmish_' + id);
+  elmish.empty(document.getElementById(id));
+  const model = {
+    todos: [
+      { id: 0, title: "Buy milk", done: false },
+      { id: 1, title: "Buy eggs", done: false },
+      { id: 2, title: "Walk the dog", done: true },
+      { id: 3, title: "Buy bread", done: true }
+    ],
+    hash: '#/active'
+  };
+
+  const model_with_search = app.update('SEARCH', model, 'Buy');
+  document.getElementById(id).appendChild(app.render_main(model_with_search, mock_signal));
+
+  t.equal(document.querySelectorAll('.view').length, 2, "two active items match 'Buy'");
+
+  elmish.empty(document.getElementById(id));
+  localStorage.removeItem('todos-elmish_' + id);
+  t.end();
+});
+
+test('10.5 Search > footer should still show original counts when searching', function (t) {
+  localStorage.removeItem('todos-elmish_' + id);
+  elmish.empty(document.getElementById(id));
+  const model = {
+    todos: [
+      { id: 0, title: "Buy milk", done: false },
+      { id: 1, title: "Buy eggs", done: false },
+      { id: 2, title: "Walk the dog", done: true }
+    ],
+    hash: '#/',
+    search: 'milk'
+  };
+
+  document.getElementById(id).appendChild(app.render_footer(model));
+
+  const count = parseInt(document.getElementById('count').textContent, 10);
+  t.equal(count, 2, "footer shows 2 items left (original count)");
+
+  const completed_count = parseInt(document.getElementById('completed-count').textContent, 10);
+  t.equal(completed_count, 1, "footer shows 1 completed item (original count)");
+
+  elmish.empty(document.getElementById(id));
+  localStorage.removeItem('todos-elmish_' + id);
+  t.end();
+});
+