The courses given at the 1st C.I.M.E. Summer School of 1988 dealt with
the main areas on the borderline between applied logic and theoretical
computer science. These courses are recorded here in five expository
papers: S. Homer: The Isomorphism Conjecture and its
Generalization.- A. Nerode: Some Lectures on Intuitionistic Logic.-
R.A. Platek: Making Computers Safe for the World. An Introduction to
Proofs of Programs. Part I. - G.E. Sacks: Prolog Programming.-
A. Scedrov: A Guide to Polymorphic T