The book is the first in a series of three volumes which explore the actual effectiveness of airpower during the 20th Century. It deals with the functions of military airpower that emerged during World War I on the Eastern and Western Fronts and in the Middle East. German strategic bombing campaigns against England by Zeppelins and Gotha bombers are described, as is their defeat by British air defenses. The book explores the development of air doctrine and the concurrent development of air forces, including those of France, Germany, Great Britain, Italy, Japan, the USSR and the United States during the 1920s and 1930s, showing their readiness for WW II on its eve. In addition, the book looks at actual conflicts during the period between WW I and WW II, and discuses the realities encountered in conflict as opposed to theories.