Several well known introductory computer science text books which use Scheme are (most notably) [Ab 85,Fr 92,Ha 94,Ma 95,Sp 89]. Development of the J programming language is relatively recent, with the first papers on J appearing in 1991. To this date, the only J based computer science text materials are [Ho 95]. However, J has been used in an expository fashion to describe several topics in mathematics [Iv 92,Iv 93,Iv 95,Re 95].