The 1998 European Summer Meeting of the Association for Symbolic Logic, Logic Colloquium '98 was held at the University of Economics in Prague, August 9-15, 1998. It was co-organized by the Academy of Sciences of the Czech Republic and the Charles University—on the occasion of the 650th anniversary of the founding of the university. During the conference, the Bolzano medal of the Academy of Sciences of the Czech Republic was presented to Gaisi Takeuti in recognition of his work in mathematical logic and other areas and for his cooperation with Czech mathematicians.

The last time a Logic Colloquium was scheduled to be held in Prague was August 1980. Unfortunately, the Czechoslovakian government cancelled that meeting about 40 days beforehand, due to fears that participants would organize protests against the imprisonment of the Czech philosopher and mathematician V. Benda (Benda is presently a senator in the Czech parliament). Nonetheless, the volume Logic Colloquium '80, containing papers intended for the cancelled meeting, was published in 1982.

The program of Logic Colloquium '98 included fifteen invited one-hour plenary addresses, three tutorials, and 39 invited half-hour lectures in parallel special sessions on computability theory, proof theory, set theory, model theory, philosophical logic and fuzzy logic. In addition, there were 98 contributed talks plus 26 papers presented by title. The number of registered participants was 241, coming from 30 countries.

The tutorial short courses were given by P. Hájek, Metamathematics of fuzzy logic; J. Krajíček, Propositional logic, arithmetic and complexity; and Z. Sela, The elementary theory of free groups.

Invited plenary addresses were given by: S.B. Cooper, Hartley Rogers’ 1965 agenda; T. Coquand, Formal topology and proof theory; A. Ekert, On some ramifications of quantum computation (joint work with R. Lupacchini); L. Fortnow, Separating classes; B. Hart, The uncountable spectra of countable theories; G. Hjorth, Vaught conjecture on analytic sets; T. Jech, Stationary sets; C. Jockusch, Ramsey's theorem, computability, and second-order number theory; L. Lipshitz,