The proliferation of databases within organizations have made it imperative to allow effective sharing of information from these disparate database systems. In addition, it is desirable that the individual systems must maintain a certain degree of autonomy over their data in order to continue to provide for their existing applications and to support controlled access to their information. Thus it becomes necessary to develop new techniques and build new functionality to interoperate these autonomous database systems and to integrate them into an overall information system. Research into interoperable database systems has advanced substantially over recent years in response to this need. The papers presented in this volume cover a wide spectrum of both theoretical and pragmatic issues related to the semantics of interoperable database systems. Topics covered include techniques to support the translation between database schema and between database languages; object oriented frameworks for supporting interoperability of heterogeneous databases, knowledge base integration and techniques for overcoming schematic discrepancies in interoperable databases. In addition, there are papers addressing issues of security transaction processing, data modelling and object identification in interoperable database systems. It is hoped the publication will represent a valuable collective contribution to research and development in the field for database researchers, implementors, designers, application builders and users alike.