On the unification free Prolog programs / K.R. Apt and S. Etalle --; Equivalences and preorders of transition systems / A. Arnold and A. Dicky --; Deliverables: a categorical approach to program development in type theory / J. McKinna and R. Burstall --; Complex and complex-like traces / Volker Diekert --; Symbolic bisimulations (abstract) / Matthew Hennessy --; Some results on the full abstraction problem for restricted lambda calculi / F. Honsell and M. Lenisa --; Action calculi, or syntactic action structures / Robin Milner --; Observable properties of higher order functions that dynamically create local names, or: What's new? / A.M. Pitts and I.D.B. Stark --; The second calculus of binary relations / Vaughan Pratt --; An introduction to dynamic labeled 2-structures / A. Ehrenfeucht and G. Rozenberg --; Post correspondence problem: Primitivity and interrelations with complexity classes / A. Mateescu and A. Salomaa --; A taste of linear logic / Philip Wadler --; On the tree inclusion problem / L. Alonso and R. Schott --; On the adequacy of per models / R. Amadio --; Hausdorff reductions to sparse sets and to sets of high information content / V. Arvind, J. Kobler and M. Mundhenk --; Stores as homomorphisms and their transformations / E. Astesiano, G. Reggio and E. Zucca --; Comparative semantics for linear arrays of communicating processes, a study of the UNIX fork and pipe commands.