The Texinfo Manual provides an introduction and a reference for using Texinfo.
Robert J. Chassell and Richard M. Stallman. Texinfo: The GNU Documentation Format, for Version 4. 1999.
The manual is distributed with the Texinfo software package, availabe online from any GNU ftp mirror, and from:
Texinfo, not unlike Emacs herself, is a massively powerful and sadly underrated tool. Read That Fine Manual and see if you don’t agree. – Anonymous