These are the proceedings of the Logic Colloquium 2006, which was held July 27–August 2 at the Radboud University of Nijmegen in the Netherlands. The Logic Colloquium is the annual European conference on logic, organized under the auspices of the Association for Symbolic Logic (ASL). The program of LC2006 consisted of a mixture of tutorials, invited plenary talks, special sessions, and contributed talks. Finally, there was a plenary discussion on Gödel’s legacy, on the occasion of the 100th birthday of the great logician Kurt Gödel, moderated by William Tait. The program gave a good overview of the recent research developments in logic. The tutorial speakers were Downey, Moerdijk, and Veli¿ckovi´c. The invited plenary speakers were Abramsky, Arslanov, Friedman, Goldstern, Hrushovski, Koenigsmann, Lewis, Montalb´an, Palmgren, Pohlers, Schimmerling, Steel, Tait, and Wagner. The five special sessions were devoted to computability theory, computer science logic, model theory, proof theory and type theory, and set theory. For these proceedings we have invited the tutorial and plenary invited speakers—as well as one invited speaker from each of the special sessions—to submit a paper. All papers have been reviewed by independent referees. This has given rise to these proceedings, which give a good overview of the content and breadth of the Logic Colloquium 2006 and of the state of the art in logic at present.