- On systems that do not permit programs to be suspended, @kbd{C-z} runs
-an inferior shell that communicates directly with the terminal, and
-Emacs waits until you exit the subshell. On these systems, the only way
-to return to the shell from which Emacs was started (to log out, for
-example) is to kill Emacs. @kbd{C-d} or @code{exit} are typical
-commands to exit a subshell.
+ To suspend Emacs, type @kbd{C-z} (@code{suspend-emacs}). This takes
+you back to the shell from which you invoked Emacs. You can resume
+Emacs with the shell command @samp{%xemacs} in most common shells.
+
+ On systems that do not support suspending programs, @kbd{C-z} starts
+an inferior shell that communicates directly with the terminal.
+Emacs waits until you exit the subshell. (The way to do that is
+probably with @kbd{C-d} or @samp{exit}, but it depends on which shell
+you use.) The only way on these systems to get back to the shell from
+which Emacs was run (to log out, for example) is to kill Emacs.
+
+ Suspending also fails if you run Emacs under a shell that doesn't
+support suspending programs, even if the system itself does support it.
+In such a case, you can set the variable @code{cannot-suspend} to a
+non-@code{nil} value to force @kbd{C-z} to start an inferior shell.
+(One might also describe Emacs's parent shell as ``inferior'' for
+failing to support job control properly, but that is a matter of taste.)
+
+ When Emacs communicates directly with an X server and creates its own
+dedicated X windows, @kbd{C-z} has a different meaning. Suspending an
+applications that uses its own X windows is not meaningful or useful.
+Instead, @kbd{C-z} runs the command @code{iconify-or-deiconify-frame},
+which temporarily closes up the selected Emacs frame.
+The way to get back to a shell window is with the window manager.