diff --git a/assets/templates/_header.phtml b/assets/templates/_header.phtml
index f419bbf..9b8a2c8 100644
--- a/assets/templates/_header.phtml
+++ b/assets/templates/_header.phtml
@@ -5,7 +5,7 @@
     <meta charset="utf-8">
 
     <title><?= $title ?? 'PHP Apprentice' ?></title>
-    <meta name="description" content="<?= $description ?? 'A site for learning how to use PHP'?>">
+    <meta name="description" content="<?= $subtitle ?? 'A site for learning how to use PHP' ?>">
     <meta name="viewport" content="width=device-width, initial-scale=1">
 
     <link rel="stylesheet" href="/css/site.css">
diff --git a/assets/templates/_table_of_contents.phtml b/assets/templates/_table_of_contents.phtml
index 21c04f8..c6d9ad9 100644
--- a/assets/templates/_table_of_contents.phtml
+++ b/assets/templates/_table_of_contents.phtml
@@ -14,6 +14,7 @@
         <li><a href="<?= page_path('classes') ?>">Classes: Introduction</a></li>
         <li><a href="<?= page_path('classes-inheritance') ?>">Classes: Inheritance</a></li>
         <li><a href="<?= page_path('classes-visibility') ?>">Classes: Visibility</a></li>
+        <li><a href="<?= page_path('classes-constructor') ?>">Classes: Constructor</a></li>
     </ol>
     <a href="<?= page_path('credits') ?>">Credits</a>
 </div>
diff --git a/assets/templates/default.phtml b/assets/templates/default.phtml
index b91a3d4..c6fcab0 100644
--- a/assets/templates/default.phtml
+++ b/assets/templates/default.phtml
@@ -1,4 +1,4 @@
-<?php partial('header', ['title' => $title, 'description' => $description]) ?>
+<?php partial('header', ['title' => $title, 'subtitle' => $subtitle]) ?>
 
 <div class="menu">
     <button class="menu-button" title="Open Menu">
diff --git a/code/classes-constructor.php b/code/classes-constructor.php
new file mode 100644
index 0000000..34adcc5
--- /dev/null
+++ b/code/classes-constructor.php
@@ -0,0 +1,47 @@
+<?php
+
+// Whenever you create an object in PHP, you put parentheses after the class name.
+// In the previous examples, we always left the parentheses empty.
+class Hat {
+    public $color;
+
+    public function setColor($color)
+    {
+        $this->color = $color;
+    }
+}
+
+$hat = new Hat();
+
+// However, you can actually pass data into the parentheses like a function.
+// The data will be passed to a special function on the class called a constructor.
+class Ballcap
+{
+    public $color;
+
+    public function __construct($color )
+    {
+        $this->color = $color;
+    }
+}
+
+// A constructor is not required, but can make creating a new object easier.
+// They are usually used to define the initial value of a property.
+// Instead of writing:
+$hat = new Hat();
+$hat->setColor('Red');
+
+// You can write:
+$ballcap = new Ballcap('Blue');
+
+// Constructors do not return values because the return value is a always a new object.
+class Tophat
+{
+    public function __construct($color)
+    {
+        return $color;
+    }
+}
+
+// "$tophat" now holds an instance of Tophat, not the color "Grey".
+$tophat = new Tophat('Grey');
diff --git a/config.php b/config.php
index 39b7303..e584669 100644
--- a/config.php
+++ b/config.php
@@ -15,84 +15,78 @@ return [
         Page::create('basics', null, 'basics.php', [
             'title' => 'Basics',
             'subtitle' => 'Getting started',
-            'description' => 'Let us get started with the basics.',
             'next' => 'variables',
         ]),
         Page::create('variables', null, 'variables.php', [
             'title' => 'Variables',
             'subtitle' => 'The building blocks of PHP',
-            'description' => '',
             'previous' => 'basics',
             'next' => 'arithmetic',
         ]),
         Page::create('arithmetic', null, 'arithmetic.php', [
             'title' => 'Arithmetic',
             'subtitle' => 'Doing math like a pro',
-            'description' => '',
             'previous' => 'variables',
             'next' => 'comparisons',
         ]),
         Page::create('comparisons', null, 'comparisons.php', [
             'title' => 'Comparisons',
             'subtitle' => 'Equality checking',
-            'description' => '',
             'previous' => 'arithmetic',
             'next' => 'boolean-logic',
         ]),
         Page::create('boolean-logic', null, 'boolean-logic.php', [
             'title' => 'Boolean Logic',
             'subtitle' => 'Is it a yes or a no?',
-            'description' => '',
             'previous' => 'comparisons',
             'next' => 'conditionals',
         ]),
         Page::create('conditionals', null, 'conditionals.php', [
             'title' => 'Conditionals',
             'subtitle' => 'Checking the if before the what',
-            'description' => '',
             'previous' => 'boolean-logic',
             'next' => 'loops',
         ]),
         Page::create('loops', null, 'loops.php', [
             'title' => 'Loops',
             'subtitle' => 'Increase your repetitions',
-            'description' => '',
             'previous' => 'conditionals',
             'next' => 'arrays',
         ]),
         Page::create('arrays', null, 'arrays.php', [
             'title' => 'Arrays',
             'subtitle' => 'Time to make a list',
-            'description' => '',
             'previous' => 'loops',
             'next' => 'functions',
         ]),
         Page::create('functions', null, 'functions.php', [
             'title' => 'Functions',
             'subtitle' => 'Reusable code',
-            'description' => '',
             'previous' => 'arrays',
             'next' => 'classes',
         ]),
         Page::create('classes', null, 'classes.php', [
             'title' => 'Classes',
             'subtitle' => 'Object-oriented programming',
-            'description' => '',
             'previous' => 'functions',
             'next' => 'classes-inheritance',
         ]),
         Page::create('classes-inheritance', null, 'classes-inheritance.php', [
-            'title' => 'Classes Inheritance',
+            'title' => 'Classes: Inheritance',
             'subtitle' => 'Extend your objects',
-            'description' => '',
             'previous' => 'classes',
             'next' => 'classes-visibility',
         ]),
         Page::create('classes-visibility', null, 'classes-visibility.php', [
-            'title' => 'Classes Visibility',
+            'title' => 'Classes: Visibility',
             'subtitle' => 'Privatizing your objects',
-            'description' => '',
             'previous' => 'classes-inheritance',
+            'next' => 'classes-constructor',
+        ]),
+        Page::create('classes-constructor', null, 'classes-constructor.php', [
+            'title' => 'Classes: Constructor',
+            'subtitle' => 'Construct your objects',
+            'previous' => 'classes-visibility',
             'next' => '',
         ]),
     ],