The Next Generation Information Technologies and Systems (NGITS) wo- shop series is a biannual event held in Israel since 1993. Like its predecessors, NGITS 99 brings together active members of the international research com- nity interested in information technology and knowledge based systems. Many of the base technologies in the traditional areas of database management systems, information retrieval, and resource optimization, are being deployed nowadays in novel systems and applications that ?ourish with the astonishing increase in computational power, storage capacity, communication, and - of course - the advent of the world-wide web. These new fronts, in turn, present an ever gr- ing set of challenges to the technologies, such as data availability, information integrity, and knowledge extraction, fuelling an exciting set of activities. Our workshop clearly re?ects this trend, o?ering a rich sample of the state of the art at the close of the millennium and a glimpse of what is to come in the next one. In response to the call for papers, we received 34 high quality submissions, 22 of which were carefully selected by the Program Committee for presentation at the workshop and inclusion in these proceedings. These include 17 full length papers as well as 5 short papers (that will be accompanied by demonstrations during the workshop). In addition, it is our pleasure to feature two invited talks, given by Professor J. Ullman of Stanford University and IBM Fellow C. Mohan."

This volume contains the proceedings of the Third International Conference on Deductive and Object-Oriented Databases. Its central tenet is that the object-oriented and deductive paradigms for modeling, organizing, and processing data complement each other, rather than competing, and that problems involving massive volumes of complex data can best be solved by integrating the best of both approaches. Central questions in the area are: - How do we design a tool that presents the best of the object-oriented and declarative ideas? - How can the users of this tool express their problems in a combination of declarative and procedural features? The volume includes 29 papers that contribute towards answering these questions.