AUC TeX: An Emacs Extension
These macros make it easier for you to write TeX documents with GNU Emacs.
Documentation can be found under: /usr/share/doc/packages/emacs-auctex/ and in the dvi files math-ref.dvi and tex-ref.dvi (reference cards) and in the info file auctex in emacs info-mode.
AuC TeX is integrated in XEmacs 19.15 and higher, so these packages may not be installed concurrently. Note that the binary formats of the byte-compiled lisp files of the two emacs editors are incompatible, so you cannot use this package for XEmacs.