Emacs stands for Editor MACroS, although opponents suggest acronyms such as Eight Megabytes and Constantly Swapping. (See also the etc/JOKES file amongst your favorite Emacs implementation to see others...) The original EMACS was written as TECO macros ; modern versions are written with C as the main engine, with extensions in LISP.
XEmacs, a near-clone of GNU Emacs
Writing GNU Emacs Extensions: Editor Customizations and Creations with Lisp (O'Reilly Nutshell)
Architecting XEmacs - Lots of XEmacs-related links
The Craft of Text Editing: Emacs for the Modern World
Once published by Springer Verlag, now available on the Web...
Emacspeak --The Complete Audio Desktop
Emacspeak is a fully functional audio desktop that provides complete eyes-free access to all major 32 and 64 bit operating environments. By seamlessly blending all aspects of the Internet such as Web-surfing and electronic messaging into the audio desktop, Emacspeak enables speech access to local and remote information with a consistent and well-integrated user interface.
EIEIO - Enhanced Integration of Emacs Interpreted Objects
A sort of CLOS/CORBA for Emacs...
This page documents the sorts of changes needed to transform XEmacs to use Common Lisp.
Implementation of a Lisp Engine Replacement
This web page documents the tasks that would be required in order to replace Emacs Lisp in XEmacs. Similar tasks would, no doubt, hold true for GNU Emacs.
IDLWAVE - editing and shell modes for GNU Emacs for IDL
Ongoing efforts are taking place to integrate other languages than ELisp with Emacs, notably:
Guile Emacs - a variant of GNU Emacs that integrates in the Guile Scheme extension language.
Guile and ELisp coexist simultaneously in this implementation.
Guile-based Emacs - converting GNU Emacs to use Guile Scheme instead of ELisp.
Support for ELisp will come via translation and/or emulation; there is no integrated ELisp "engine" in the system.
Perlmacs is a program based on GNU Emacs with the Perl interpreter linked in.
Why I became an Emacs user Or, My long arduous journey to the One True Editor
Table.el is an Emacs Lisp package that extends Emacs and provides text based table creation and editing feature. With this package Emacs is capable of editing tables that are embedded inside a document, the feature similar to the ones seen in modern WYSIWYG word processors.
It uses the commonly used SGML CALS table system.
A comprehensive Emacs mode for managing inferior Lisp modes for Common Lisp, Scheme, and other Lisp-based languages
SLIME - Superior Lisp Interaction Mode for Emacs
Intended as a better mode than ilisp for Common Lisp
An article (well, a blog "rant") on how to use Emacs more effectively. An excellent set of tips...
Various editors have emulated Emacs over the years, removing the LISP component architecture, primarily so that they could reduce the memory footprint.
Uses an interpreted stack-based extension language called SLANG that is also used in the slrn news reader and the Mutt mail client.
A venerable Emacs "clone" that has run on small systems for about a dozen years now.
Efuns an Emacs-like editor written using Objective CAML
JEmacs @ SourceForge.net - a re-implementation of Emacs, written in a mix of Java, Scheme, and Emacs Lisp (ELisp). Based on Kawa.
Christopher Rath's set of keyboard macros for MS Word to make it behave somewhat like Emacs. (I knew him back in Ottawa in my Atari days...)
A text editor offering vi and Emacs keybindings that can be as small as 12K in size, making it good for things like rescue disks.
This wishes to be the comprehensive "implementing Emacs in Common Lisp " project. Based on Hemlock (part of CMU/CL), this is undergoing continued development...
For those wishing to web browse with total keyboard control...