Circuit design is now carried out by computers using algorithms instead of tables, charts and rules of thumb. The book is an introduction to the computer-aided design of communication networks, based on a firm analytic foundation of circuit theory and numerical techniques. It provides design procedures and techniques of filters, broadband matching networks, compatible impedances, high-frequency amplifiers, diplexers and multiplexers. All programs are written in FORTRAN 77 and run by MS-FORTRAN 5.1 and WATFIV compilers on personal computers. A special feature of the book is that it bridges the gap between theory and practice, and algorithms and implementations. The level of the book is suitable for a senior elective or a circuit design course for the first-year graduate students as well as a reference book for practicing engineers.