Logic Colloquium ‘79 was held at the University of Leeds, England, from 5–14 August, 1979. It was organised by the British Logic Colloquium and recognised as the European Summer Meeting of the Association for Symbolic Logic, and was co-sponsored by the School of Mathematics of Leeds University.

Financial assistance was received from the British Academy, the British Council, the International Union for the History and Philosophy of Science, the London Mathematical Society, and the Royal Society. We wish to record our thanks to these bodies.

Short courses of lectures and one-hour lectures were given as follows:

R.I. Soare (4 lectures) Recursively enumerable sets and degrees.

S.G. Simpson (2 lectures) Admissible recursion theory.

R.A. Shore (2 lectures) Admissible recursion theory.

D. Normann (2 lectures) Recursion on the countable functionals.

G. Sundholm (2 lectures) ω-Arithmetic and recursive progressions.

R. Ladner (4 lectures) Complexity theory and the complexity of logical theories.

D.B. Posner, The non-r.e. degrees < O'.

C.G. Jockusch, Degrees of generic sets.

M. Lerman, Recent results on the degrees of unsolvability.

G.E. Sacks, Three theorems on recursive enumerability in a normal object of finite type.

J.V. Tucker, The computable functions of abstract algebra.

C.H. Smith, Applications of recursion theory to computer science.

D. Alton, Natural programming languages and complexity measures for subrecursive programming languages.

w. Paul, Time and space bounded computations.

L. Valiant, Non-computational reducibilities.

K. McAloon, On the structure of models of arithmetic.

Papers based on 11 of the above talks are published in this volume. In addition, there were 19 contributed papers, abstracts of which are published in the Journal of Symbolic Logic, vol. 45.