While teaching a data structures course at University of California, Irvine, I developed a program called GPERF that generates perfect hash functions for sets of key words. A perfect hash function is simply: A hash function and a data structure that allows recognition of a key word in a set of words using exactly 1 probe into the data structure. The gperf.texinfo file explains how the program works, the form of the input, what options are available, and hints on choosing the best options for particular key word sets. The texinfo file is readable both via the GNU emacs `info' command, and is also suitable for typesetting with TeX. The enclosed Makefile creates the executable program ``gperf'' and also runs some tests. Output from the GPERF program is used to recognize reserved words in the GNU C, GNU C++, and GNU Pascal compilers, as well as with the GNU indent program. LICENSE: GPLv3 or later