Dear Haskell-list members, This is to advertise the monograph Synthetic topology of data types and classical spaces, to appear in ENTCS 87, 150pp, three parts, 6+5+2 chapters. http://www.cs.bham.ac.uk/~mhe/papers/entcs87.pdf (or .dvi or .ps) Chapter 3 develops topology in Haskell, without assuming any previous knowledge of topology. Notions of topology such as space, continuous map, open set, closed set, discrete space, Hausdorff space, compact space are defined directly in the programming language. Theorems in topology are proved by writing programs. The development here is purely operational. This gives some surprising results, e.g. that the type ((Int->Bool)->Int) has decidable equality (for total elements). Chapter 12 has more sophisticated computational applications, which invoke classical topology with the aid of denotational semantics. We apply the Tychonoff theorem of classical topology to show that a certain (we hope surprising) Haskell program has the correct termination properties. Martin Escardo