The papers in this volume were presented at theInternational Conference on Database Theory, held in Berlin,Germany, October 14-16, 1992. This conference initiated themerger of two series of conferences on theoretical aspectsof databases that were formed in parallel by differentscientific communities in Europe. The first series was knownas the International Conference on Database Theory and thesecond as the Symposium on Mathematical Fundamentals ofDatabase Systems. In the future, ICDT will be organizedevery two years, alternating with the more practicallyoriented series of conferences on Extending DatabaseTechnology (EDBT).The volume contains 3 invited lectures and 26 contributedpapers selected from a total of 107 submissions. The papersare organized into sections on constraints anddecomposition, query languages, updates and activedatabases, concurrency control and recovery, knowledgebases, datalog complexity and optimization, objectorientation, information capacity and security, and datastructures and algorithms. Two of the invited papers surveyresearch into theoretical database issues done in EasternEurope during the past decade.