Because the direction to targets is usually expressed by the direction of arrival (DOA) of transmitted signals, determining the direction of arrival (DOA) of any signal is of critical importance to electrical engineers working on both civilian and tactical applications in radar and communications. This cutting-edge resource presents the latest developments in DOA estimation from the leading researchers in the field. The first compiled book in the field, this in-depth reference covers a wide range of key topics, from DOA estimation methods and source localization problems, to specific applications of DOA estimation and experimental setup and results. Practitioners discover how DOA estimation is one of the main functional requirements for direction-finding smart antennas in next generation mobile and stealth communication systems. The book also serves as an excellent text for graduate students and researchers studying in this area.