GNU Emacs is probably the most popular form of Emacs available today.
Maintainer: Free Software Foundation Homepage: http://www.gnu.org/software/emacs Manual: http://www.gnu.org/software/emacs/manual/html_mono/emacs.html Wiki: http://www.emacswiki.org Newsgroups: http://groups.google.com/groups?group=gnu.emacs.help http://groups.google.com/groups?group=comp.emacs EmacsW32: http://ourcomments.org/Emacs/EmacsW32.html Family: EmacsFamily License: GPL Platform: GNU/Linux?, FreeBSD, AIX 4.3.3 and higher, Mac OS X, MS-DOS, MS Windows, NetBSD, OpenBSD, Solaris, SunOS?, Ultrix, others
Gnu Emacs is the lineal descendant of the original "Editing MACroS" product, written in TECO by Richard M. Stallman (RMS) for the ITS system at MIT. Gnu Emacs was rewritten in C by RMS, using the Emacs Lisp dialect of Lisp for most core functions. Because Gnu Emacs is mostly written in Lisp, it is extensible via Lisp code, and many extensions for specialized tasks exist, including "major modes" for reading and replying to email and reading and replying to Usenet Newsgroups.
It is maintained by thousands of developers and available most easily from the Free Software Foundation. (As part of GNU project, it was coincidently the first GNU software)