Physical Layer Security in Wireless Communications supplies a systematic overview of the basic concepts, recent advancements, and open issues in providing communication security at the physical layer. It introduces the key concepts, design issues, and solutions to physical layer security in single-user and multi-user communication systems, as well as large-scale wireless networks. Presenting high-level discussions along with specific examples, and illustrations, this is an ideal reference for anyone that needs to obtain a macro-level understanding of physical layer security and its role in future wireless communication systems.