Colonel Williams presents a comprehensive study of British bombing efforts in the Great War. He contends that the official version of costs and results underplays the costs while overplaying the results. Supported by postwar findings of both US and British evaluation teams, he argues that British bombing efforts were significantly less effective than heretofore believed. Colonel Williams also presents a strong argument that German air defenses caused considerably less damage to British forces than pilot error, malfunctioning aircraft, and bad weather. That we believed otherwise supports the notion that British bombing raids had forced Germany to transfer significant air assets to defend against them. Williams, however, found no evidence that any such transfer occurred. Actual results, Colonel Williams argues, stand in strong contrast to claimed results.