This book presents the fundamentals of operating systems that remain constant as new, more advanced systems are introduced and also integrates and highlights key distributed operating systems issues. The main topics presented include message-based synchronization and remote procedure calls, as well as unique integration of distributed deadlocks, distributed shared memory, distributed file systems, and secure communication using cryptography. For systems programmers, software engineers, programmers, and other professionals who want to teach themselves the fundamentals of operating systems or enhance their understanding of operating systems and distributed systems issues.