This is the first book to cover comprehensively the mathematical theory of nonblocking switching networks since Beneš' book published 30 years ago. Not only is the material on the classical theory of nonblocking and rearrangeable networks updated, but the modern topics on multicast and multirate switching are also surveyed. The author had spent more than 25 years working on switching networks at Bell Laboratories before he started teaching the course at Chiao-Tung University. He has published about 40 papers and obtained a dozen patents on multistage interconnection networks.