Book excerpt: At the end of the Great War, the U.S. Army faced the challenge of integrating what it had learned in the failures and ultimate success of its war effort. During the interwar years the army sought to balance readiness and modernization in a period of limited resources and technological advances with profound implications for the conduct of warfare. In After the Trenches, William O. Odom traces the development of combat doctrine between the world wars through an examination of the army's primary doctrine manuals, the Field Service Regulations. The Field Service Regulations of 1923 successfully assimilated the experiences of the First World War and translated them into viable tactical practice, Odom argues in this unique study. Rapidly developing technologies generated more efficient tools of war and greatly expanded the scale, tempo, and complexity of warfare. Personnel and materiel shortages led to a decline in the quality of army doctrine evidenced in the 1939 regulations. Examining the development of doctrine and the roles of key personalities such as John Pershing, Hugh Drum, George Lynch, Frank Parker, and Lesley McNair, Odom concludes that the successive revisions of the manual left the army scurrying to modernize its woefully outdated doctrine on the eve of the new war. This impressively researched study of the doctrine of the interwar army fills a significant gap in our understanding of the development of the U.S. Army during the first half of the twentieth century. It will serve scholars and others interested in military history as the standard reference on the subject. Moreover, many of the challenges and conditions that existed seventy years ago resemble those faced by today's army. This study of the army's historical responses to a declining military budget and an ever-changing technology will broaden the perspectives of those who must deal with these important contemporary issues.