Real-time systems are defined as those for which correctness depends not only on the logical properties of the produced results, but also on the temporal properties of these results. In a database, real-time means that in addition to typical logical consistency constraints, such as a constraint on a data item’s value, there are constraints on when transactions execute and on the freshness of the data transactions access. The challenges and tradeoffs faced by the designers of real-time database systems are quite different from those faced by the designers of general-purpose database systems. To achieve the fundamental requirements of timeliness and predictability, not only do conventional methods for scheduling and transaction management have to be redesigned, but also new concepts that have not been considered in conventional database systems or in real-time systems need to be added. This book is devoted to techniques for scheduling of transactions, concurrency management, transaction logging, database languages, and new distributed database architectures. The book is primarily intended for practicing engineers and researchers working in the growing area of real-time database and information retrieval systems. For practitioners, the book should provide a bridge for technology transfer and continued education. For researchers, the book should provide a comprehensive reference for well-established results. The book can also be used in a senior or graduate level course on real-time systems, real-time database systems, and database systems, or closely related courses.