Book excerpt: [Includes 13 charts, and 46 illustrations] This book forms part of the “Vietnam Studies” series produced by various senior commanders who had served in the U.S. Army during the Vietnam War; each officer was chosen for their knowledge of the number of specialized subjects that were covered by the series. The challenge facing the General McChristian in 1965 was exceptionally daunting, as deputy head of General Westmoreland’s Intelligence section his orders were clear he was told that he must "Find the enemy!". A daunting task in a country filled with insurgents, uniformed enemy using other countries to move toward their targets, double agents, spies and a South Vietnamese Intelligence service to be integrated into his plans. As he himself put it: “I knew that finding the enemy was only part of the challenge. Our soldiers would have to fix and fight him. They would need to know enemy strength, capabilities, and vulnerabilities as well as information on the weather and terrain. Such intelligence had to be timely, accurate, adequate, and usable. It was to be my job to build an organization to meet that challenge.” It is remarkable that he achieved a good measure of success in his task in only two years in a country with so many endemic issues, and even more so that he was able to distil his story and of his department in to this detailed but very readable exposition of the Intelligence services in Vietnam. A complex and engaging study of a very difficult job done well.