The establishment of the Defense Intelligence Agency was the result of a confluence of long-term and short-term trends. Seen over the long duration, the creation of DIA was a part of the extended process of centralisation in the Department of Defense that had been taking place since the National Security Act created the department. This book is designed to provide an understanding of the Defense Intelligence Agency's participation in military and intelligence developments of the last half century. While history does not repeat itself, it does provide context, guideposts, and a framework for understanding the present. In some ways, the challenges discussed in this book and confronting today's Intelligence Community personnel are similar to those faced by their cohorts from earlier generations.