The Army Materials and Mechanics Research Center in coop­ eration with the Materials Science Group of the Department of Chemical Engineering and Materials Science of Syracuse University has been conducting the Annual Sagamore Army Materials Research Conference since 1954. The specific purpose of these conferences has been to bring together scientists and engineers from academic institutions, industry and government who are uniquely qualified to explore in depth a subject of importance to the Department of Defense, the Army and the scientific community. These proceedings, entitled RESIDUAL STRESS AND STRESS RELAXATION, address the nature of residual stresses and their measurements, the sources of residual stress, stress relaxation, sub-critical crack growth in the presence of residual stress, residual stresses and properties, and research in progress. We wish to acknowledge the assistance of Mr. Dan McNaught of the Army Materials and Mechanics Research Center and Mr. Robert J. Sell and Helen Brown DeMascio of Syracuse University throughout the stages of the conference planning and finally the publication of the book. The continued active interest and support of these conferences by Dr. E. Wright, Director of the Army Materials and Mechanics Research Center, is appreciated.