Book excerpt: The U.S. did not become the world's foremost military air power by accident. The learning curve--World War I, World War II, the Korean War, the Vietnam War, the Gulf War, and more recently the war on terror--has been steep. While climbing this curve, the U.S. has not only produced superior military aircraft in greater numbers than its foes, but has--in due course--out-trained them, too. This book provides a comprehensive historical survey of U.S. military training aircraft, including technical specifications, drawings and photographs of each type of fixed and rotary-wing design used over a 98-year period to accomplish the first step of the learning process: the training of pilots and aircrews.