It can take awhile to figure out all the shortcuts and features in the ever-growing list of Google web applications. The Google Operating System blog unearths a quick URL hack to display a Google app's entire help file—normally split up on cross-linked pages—in easily-saved and printable HTML. Head to the app's "support center," usually found at, for example, mail.google.com/support/, and add ?fulldump=1 to the end of the URL. Hit the Google Operating System link for direct, download-able links to the most popular apps' full help files.
Download Google's Help Files