diff --git a/doc/manual/configuration.xml b/doc/manual/configuration.xml
index 6a217243c00..3ff8ca8f240 100644
--- a/doc/manual/configuration.xml
+++ b/doc/manual/configuration.xml
@@ -392,6 +392,60 @@ groups can be managed using <command>groupadd</command>,
 </section>
 
 
+<!--===============================================================-->
+
+<section><title>X11</title>
+
+<para>The X11 windowing system provides the basis of NixOS’ graphical
+user interface.  It can be enabled as follows:
+<programlisting>
+services.xserver.enable = true;
+</programlisting>
+The X server will automatically detect and use the appropriate video
+driver from a set of X.org drivers (such as <literal>vesa</literal>
+and <literal>intel</literal>).  You can also specify a driver
+manually.  For instance, to enable the proprietary NVIDIA driver, you need
+<programlisting>
+services.xserver.videoDrivers = [ "nvidia" ];
+</programlisting>
+(You may need to reboot after enabling this driver to prevent a clash
+with other kernel modules.)</para>
+
+<para>You also need to enable at least one desktop or window manager.
+Otherwise, you can only log into a plain undecorated
+<command>xterm</command> window.  Thus you should pick one or more of
+the following lines:
+<programlisting>
+services.xserver.desktopManager.kde4.enable = true;
+services.xserver.desktopManager.xfce.enable = true;
+services.xserver.windowManager.xmonad.enable = true;
+services.xserver.windowManager.twm.enable = true;
+services.xserver.windowManager.icewm.enable = true;
+</programlisting>
+</para>
+
+<para>NixOS’s default <emphasis>display manager</emphasis> (the
+program that provides a graphical login prompt and manages the X
+server) is SLiM.  You can select KDE’s <command>kdm</command> instead:
+<programlisting>
+services.xserver.displayManager.kdm.enable = true;
+</programlisting>
+</para>
+
+<para>The X server is started automatically at boot time.  If you
+don’t want this to happen, you can set:
+<programlisting>
+services.xserver.autorun = false;
+</programlisting>
+The X server can then be started manually:
+<screen>
+$ systemctl start display-manager.service
+</screen>
+</para>
+
+</section>
+
+
 <!--===============================================================-->
 
 <section><title>Networking</title>
@@ -573,8 +627,7 @@ networking.localCommands =
 </section>
 
 
-<!-- TODO: declarative package installation; X11; user management;
-     Apache; libvirtd virtualisation -->
+<!-- Apache; libvirtd virtualisation -->
 
 
 </chapter>