diff --git a/src/Entity/Browser/Menu/Help/About.php b/src/Entity/Browser/Menu/Help/About.php
index 94fc3d1a..ae9fa9a6 100644
--- a/src/Entity/Browser/Menu/Help/About.php
+++ b/src/Entity/Browser/Menu/Help/About.php
@@ -5,7 +5,13 @@ declare(strict_types=1);
 namespace Yggverse\Yoda\Entity\Browser\Menu\Help;
 
 use \Gtk;
+use \GtkButtonsType;
+use \GtkDialogFlags;
+use \GtkJustification;
 use \GtkMenuItem;
+use \GtkMessageDialog;
+use \GtkMessageType;
+use \GtkResponseType;
 
 use \Yggverse\Yoda\Entity\Browser\Menu\Help;
 
@@ -20,6 +26,14 @@ class About
     // Defaults
     public const LABEL = 'About';
 
+    public const DIALOG_MESSAGE_FORMAT = 'About';
+    public const DIALOG_FORMAT_SECONDARY_MARKUP_APP_SRC_VERSION = '<a href="https://github.com/YGGverse/Yoda"><span underline="none">Yoda</span></a> dev'; // @TODO
+    public const DIALOG_FORMAT_SECONDARY_MARKUP_PHP_SRC_VERSION = '<a href="https://github.com/php/php-src"><span underline="none">PHP</span></a> %d.%d.%d';
+    public const DIALOG_FORMAT_SECONDARY_MARKUP_PHP_GTK_VERSION = '<a href="https://github.com/scorninpc/php-gtk3"><span underline="none">PHP-GTK</span></a> %s';
+    public const DIALOG_FORMAT_SECONDARY_MARKUP_LIB_GTK_VERSION = 'GTK %d.%d.%d';
+
+    public const PHP_VERSION_GTK_EXTENSION = 'php-gtk3';
+
     public function __construct(
         Help $help
     ) {
@@ -39,7 +53,72 @@ class About
             'activate',
             function()
             {
-                // @TODO
+                $dialog = new GtkMessageDialog(
+                    $this->help->menu->browser->gtk,
+                    GtkDialogFlags::MODAL,
+                    GtkMessageType::INFO,
+                    GtkButtonsType::OK,
+                    _($this::DIALOG_MESSAGE_FORMAT)
+                );
+
+                $dialog->format_secondary_markup(
+                    implode(
+                        PHP_EOL,
+                        [
+                            _($this::DIALOG_FORMAT_SECONDARY_MARKUP_APP_SRC_VERSION),
+                            sprintf(
+                                _($this::DIALOG_FORMAT_SECONDARY_MARKUP_PHP_SRC_VERSION),
+                                PHP_MAJOR_VERSION,
+                                PHP_MINOR_VERSION,
+                                PHP_RELEASE_VERSION
+                            ),
+                            implode(
+                                ' / ',
+                                [
+                                    sprintf(
+                                        _($this::DIALOG_FORMAT_SECONDARY_MARKUP_PHP_GTK_VERSION),
+                                        phpversion(
+                                            $this::PHP_VERSION_GTK_EXTENSION
+                                        )
+                                    ),
+                                    sprintf(
+                                        _($this::DIALOG_FORMAT_SECONDARY_MARKUP_LIB_GTK_VERSION),
+                                        0, // @TODO pending for PR #153
+                                        0,
+                                        0
+                                    )
+                                ]
+                            )
+                        ]
+                    )
+                );
+
+                // Tune up the label
+                if ($label = $dialog->get_message_area()->get_children())
+                {
+                    if (!isset($label[1]))
+                    {
+                        throw new Exception;
+                    }
+
+                    $label[1]->set_selectable(
+                        true
+                    );
+
+                    $label[1]->set_track_visited_links(
+                        false
+                    );
+
+                    $label[1]->set_justify(
+                        GtkJustification::CENTER
+                    );
+                }
+
+                // Await for action
+                if (GtkResponseType::OK == $dialog->run())
+                {
+                    $dialog->destroy();
+                }
             }
         );
     }