Debra Cameron 
GNU Emacs Pocket Reference [PDF ebook] 
UNIX Text Processing

GNU Emacs is the most popular and widespread of the Emacs family of editors. It is also the most powerful and flexible. Unlike all other text editors, GNU Emacs is a complete working environment — you can stay within Emacs all day without leaving. The GNU Emacs Pocket Reference is a companion volume to O’Reilly’s Learning GNU Emacs, which tells you how to get started with the GNU Emacs editor and, as you become more proficient, it will help you learn how to use Emacs more effectively.This small book, covering Emacs version 20, is a handy reference guide to the basic elements of this powerful editor, presenting the Emacs commands in an easy-to-use tabular format.