CHMLIB is a library for dealing with Microsoft ITSS/CHM format files. Right
now, it is a very simple library, but sufficient for dealing with all of the
.chm files I've come across. Due to the fairly well-designed indexing built
into this particular file format, even a small library is able to gain
reasonably good performance indexing into ITSS archives.

WWW: http://www.jedrea.com/chmlib/