This article is from the GNU Chess and XBoard FAQ, by Tim Mann firstname.lastname@example.org with numerous contributions by others.
There is a port of GNU Chess 4.0 to the Macintosh. It's available from
the Internet Chess Library (topic [A.3] ) under /pub/chess/Macintosh or
/pub/chess/uploads/Macintosh, in the following files:
GnuChessMac40b5.hqx - executable binary GCMsource40b5.hqx - source