The Army Materials and Mechanics Research Center has conducted the Sagamore Army Materials Research Conferences, in cooperation with the Metallurgical Research Laboratories of the Department of Chemical Engineering and Metallurgy of Syracuse University, since 1954. The purpose of the conferences has been to gather together scientists and engineers from academic institutions, industry, and government who are uniquely qualified to explore in depth a subject of importance to the Army, the Department of Defense and the scientific corr.munity. This volume, Surfaces and Interfaces ll: Physical and Mechanical Properties, can be considered a continuation, or perhaps an extension, of the information contained in Surfaces and Interfaces I: Chemical and Physical Characteristics. The emphasis in this volume is focused on: the technological significance of surfaces and interfaces; surface­ sensitive mechanical properties; environment-sensitive properties; control of grain structure; and composite materials. It is felt that the rather ambitious undertaking of the program committee to place the role of "surfaces and interfaces" in its proper context has been achieved. The balance between basic research findings and more applied research allows the reader a certain degree of latitude in the use of the two volumes. The continued active interest and support of these conferences by Col. C. T. Riordan, Commanding Officer, Dr. E. Scala, Technical Di­ rector, and J. F. Sullivan, Deputy Technical Director, of the Army Materials and Mechanics Research Center is appreciated.

Learning to Forget analyzes the evolution of US counterinsurgency (COIN) doctrine over the last five decades.