Shared memory multiprocessors are becoming the dominant architecture for small-scale parallel computation. This book provides a coherent review of current research in shared memory multiprocessing in the United States and Japan. It focuses particularly on scalable architectures that will be able to support hundreds of microprocessors as well as on efficient and economical ways of connecting these fast microprocessors. The 20 contributions are divided into sections covering the experience to date with multiprocessors, cache coherency, software systems, and examples of scalable shared memory multiprocessors.