Two Emacs manuals, the GNU Emacs manual and An Introduction to Programming in Emacs Lisp, can be purchased in printed form from the FSF store.
These manuals, along with the Emacs Lisp Reference Manual and several other manuals documenting major modes and other optional features, can also be read online. They are also distributed with Emacs in Info format; type C-h i in Emacs to view them.
The Emacs distribution includes the full source code for the manuals, as well as several Emacs Reference Cards in various languages.
To ask for help with GNU Emacs, use the mailing list firstname.lastname@example.org or the newsgroup gnu.emacs.help. The mailing list and newsgroup are linked: messages posted on one appear on the other as well.
To report bugs, or to contribute fixes and improvements, use the built-in Emacs bug reporter (M-x report-emacs-bug) or send email to email@example.com. You can browse our bug database at debbugs.gnu.org. For more information on contributing, see the CONTRIBUTE file (also distributed with Emacs).
For all other queries, consult the list of Emacs-related mailing lists on savannah.gnu.org and the complete list of GNU mailing lists on lists.gnu.org. See Get Help with GNU Software for help with GNU software in general.