This volume covers both theoretical and practical aspects of distributed computing. It describes the client-server model for developing distributed network systems, the communication paradigms used in a distributed network system, and the principles of reliability and security in the design of distributed network systems. Based on theoretical introductions, the book presents various implementation strategies and techniques for building distributed network systems, including examples in TCP/IP communications, the use of remote procedure call and remote method invocation techniques, and the development of web-based applications, distributed databases, and mobile computing systems.