GNU hypertext utilities to view and manipulate info
documentation files.

The  GNU  project has a hypertext system called Info which
allows the same source file to  be  either  printed  as  a
paper manual, or viewed using info.  It is possible to use
the info program from inside Emacs, or to use  the  stand-
alone  version  described  here.

Homepage:
http://www.gnu.org/software/texinfo/texinfo.html
