This text illustrates the main issues and concepts behind deductive databases through the description of a real system. Both theory and practice combine to advance a pragmatic approach. The book covers all related topics from basic theory to its coupling with a known database management system and its implementation on a commerical multiprocessor. An overview describes the problems related to the field. In the introduction, basic tools and references to related work give the necessary background context. Chapter two slowly begins building the concepts that finally lead to the kern algorithm used throughout the book - mixed top-down, bottom-up computation. Upon completion of the book, the reader should be able to build a deductive database. Implementation problems are exposed and solved and new strategies and algorithms with their performance behaviour are presented. Additionally the reader should also learn the benefits and drawbacks of working with an existing database and the usefulness of a parallel machine.