This work is concerned with the way in which the computer in its simplest form is a component in a system which can be used to construct complex computer architectures. Fundamental aspects of digital computers, such as stored programs, data representatic and arithmetic are covered, although it is assumed that students will have some knowledge of digital systems. The early chapters are used to establish a basic understanding of the essentials of digital systems and microprogramming before going on to consider the implementation of microprocessors in computer systems. The chapters on memory systems and input/output systems have been rewritten, and there are new sections on advanced computer architectures, including parallel processing and RISC architecture and computer networks such as local area networks. The final chapter deals with testing and reliability of computer systems and the use of software tools in system design. Each chapter features numerous worked examples and problems with the full worked solutions given at the end of the book. Comprehensive references to the literature are also provided at the end of each chapter.