This volume represents the outcome of the International Conference on "Extending Database Technology", held in Venice, Italy, in March 1988. It contains the major dimensions into which database technology is currently being pushed by the needs of new applications and pulled by the chances of novel developments in hardware and systems architecture. The two broad areas covered are: extended database semantics: data models and data types, databases and logic, complex objects, and expert system approaches to databases; and new architectures and increased database systems support: novel transaction models, data distribution and replication, database administration and access efficiency. Since an increasing amount of database research and development is done through international cooperation and within joint projects (ESPRIT, EUREKA, industrial cooperations), a substantial part of the book is dedicated to representing about a dozen advanced database projects on data- and knowledge-based systems and on distributed database applications by their aims, status, and results.