This book describes the machine model designed to support parallel inference, t5he design of the Kleng language, the design and implementation of the parallel inference engine, the programming tools, the runtime system, and some evaluation results. The architecture of the PIE 64 is tuned specially to support parallel inference. The compiler and runtime system proposed here are designed to reduce the overhead that is inevitably incurred when we use fine granularity processing. We can expect a much higher degree of parallelism by using parallel logic programming languages such as Fleng, especially when it is difficult to gain any extra parallelism from description in conventional languages such as C or Fortran. We believe that the results of this research will be useful for designing a new high-performance processor/computer architecture.