+@node MS-Windows Registry
+@appendixsubsec The MS-Windows System Registry
+@pindex addpm, MS-Windows installation program
+@cindex registry, setting environment variables and resources on MS-Windows
+
+On MS-Windows, the installation program @command{addpm.exe} adds values
+for @env{emacs_dir}, @env{EMACSLOADPATH}, @env{EMACSDATA},
+@env{EMACSPATH}, @env{EMACSDOC}, @env{SHELL} and @env{TERM} to the
+@file{HKEY_LOCAL_MACHINE} section of the system registry, under
+@file{/Software/GNU/Emacs}. It does this because there is no standard
+place to set environment variables across different versions of
+Windows. Running @command{addpm.exe} is no longer strictly
+necessary in recent versions of Emacs, but if you are upgrading from
+an older version, running @command{addpm.exe} ensures that you do not have
+older registry entries from a previous installation, which may not be
+compatible with the latest version of Emacs.
+
+When Emacs starts, as well as checking the environment, it also checks
+the System Registry for those variables and for @env{HOME}, @env{LANG}
+and @env{PRELOAD_WINSOCK}.
+
+To determine the value of those variables, Emacs goes through the
+following procedure. First, the environment is checked. If the
+variable is not found there, Emacs looks for registry keys by that
+name under @file{/Software/GNU/Emacs}; first in the
+@file{HKEY_CURRENT_USER} section of the registry, and if not found
+there, in the @file{HKEY_LOCAL_MACHINE} section. Finally, if Emacs
+still cannot determine the values, compiled-in defaults are used.
+
+In addition to the environment variables above, you can also add many
+of the settings which on X belong in the @file{.Xdefaults} file
+(@pxref{X Resources}) to the @file{/Software/GNU/Emacs} registry key.
+Settings you add to the @file{HKEY_LOCAL_MACHINE} section will affect
+all users of the machine. Settings you add to the
+@file{HKEY_CURRENT_USER} section will only affect you, and will
+override machine wide settings.
+