All naval professionals—without exception—encounter, directly participate, or play a supporting role in naval cooperation. It is a key element in the U.S. defense strategy because military and naval operations today are usually conducted by international coalitions and fighting alongside foreign navies is an expected aspect of current and future naval warfare. Activities in support of mutual defense include bilateral and multilateral exercises, international programs such as cooperative acquisition and foreign military sales, combined training, and efforts towards increased interoperability. This volume is intended to provide a basic familiarization to all aspects of the subject and detailed understanding of relevant recent issues. Since there is no formal training offered on the subject for naval professionals—with the exception of certain specialized personnel—the book is designed to bridge the existing gap in knowledge about naval cooperation.