This book describes the design and internals of the MOSIXdistributed operating system. MOSIX, an acronym forMulticomputer Operating System for UNIX, integrates acluster of loosely integrated computers into a virtualsingle-machine UNIX environment. The main property of MOSIXis the high degree of integration among the processors,which may include personal workstations and shared memoryand non-shared memory multiprocessors, connected by fastcommunication links. This integration includes networktransparency, cooperation between the processors to provideservices across machine boundaries, support of dynamicconfiguration, and system-initiated load balancing byprocess migration. Another property of MOSIX is the abilityto scale up the system configuration to encompass a largenumber of computers. The development of MOSIX was begun in1981. The book is intended primarily for readers who areinterested in distributed and multiprocessor systems. Thereader is assumed to have some knowledge in programming andoperating systems, preferably UNIX. Readers without thisbackground will still benefit from thetechniques andalgorithms discussed.