The first draft of this study was written in 1944-45. This draft is being reproduced with minor revision. It has some unfinished portions, and certain important aspects of air-ground cooperation, such as airborne and antiaircraft artillery training and air supply. The record of the performance of the air-ground battle team in theaters of operations was likewise incomplete when this draft was compiled. The purpose of reproducing this study is to explain the responsibilities and outlook of Army Ground Forces with reference to air power and air-ground cooperation during World War II. Partial Contents: American Doctrine Regarding the Employment of Air Power, Responsibilities and Outlook of General NcNair, Air-Ground Training in 1942, Organic Aviation in Field Artillery, 1942, Air-Ground Training in 1943, Revision of AAF Doctrine and Organization, 1943, Organic Ground Force Aviation, January 1943-June 1944, Practical Steps toward Air-Ground Cooperation, Developments in the European and Pacific Theaters, 1944-1945, Organic Ground Aviation in Combat, Air-Ground Doctrine and Organization.