Book excerpt: Written by an internationally recognized as an expert on the subject of microwave (MW) tubes, this book presents and describes the many types of microwave tubes, and despite competition from solid-state devices (those using GaN, SiC, et cetera), which continue to be used widely and find new applications in defense, communications, medical, and industrial drying. Helix traveling wave tubes (TWTs), as well as coupled cavity TWTs are covered. Klystrons, and how they work, are described, along with the physics behind it and examples of devices and their uses. Vacuum electron devices are explained in detail and examines the harsh environment that must exist in tubes if they are to operate properly. The secondary emission process and its role in the operation of crossed-field devices is also discussed. The design of collectors for linear-beam tubes, including power dissipation and power recovery, are explored. Discussions of important noise sources and techniques that can be used to minimize their effects are also included. Presented in full color, this book contains a balance of practical and theoretical material so that those new to microwave tubes as well as experienced microwave tube technicians, engineers, and managers can benefit from its use.