Mike Leahy is the author of the Bookup chess programs. Bookup itself was the first to appear in 1984 for DOS. Bookup was recently replaced by Chess Openings Wizard for Windows XP, 2000 and Vista.
Mike also programmed MasterChess 6000 (on dual layer DVD) for Windows and also Essentia for Macintosh, two massive game database research programs.
In 1993 Mike created the Bobby Fischer Teaches Chess CD ROM which is no longer available.