Suitable for researchers and graduate students in computer science, electrical engineering, and applied mathematics, this book presents a concise yet complete account of the most significant results in interconnection network theory. The authors give a mathematical classification and characterization of the key interconnection functions of networks and establish their switching factor complexities using combinatorial methods. The text leads readers through the historical development, covering major contributions from Shannon, Clos, Benes, Cantor, Pinsker, and Margulis. It also explores recent results, such as quantum switching networks.