Slightly OT: those who enjoyed Norvig's PAIP but wanted more AI content will enjoy Forbus and de Kleer's Building Problem Solvers. Starts out on the same subjec

Slightly OT: those who enjoyed Norvig's PAIP but wanted more AI content will enjoy Forbus and de Kleer's Building Problem Solvers. Starts out on the same subject matter as PAIP but spends a lot of time talking about truth maintenance system. The code is in Common Lisp. It's old-style symbolic AI which is fairly limited in its utility, but truth maintenance systems have interesting applications in natural language processing and and other domains, so, whatever.