"The Engines of Pratt & Whitney: A Technical History" describes the evolution from piston engines to gas turbines by the engineers who created those engines. Included are hundreds of archival photographs, as well as over a dozen tables listing specifications and applications. The story starts with the founding of the company in the 1920s to provide reliable air-cooled piston engines to the military and to help create coast-to-coast commercial flight service. Pratt & Whitney quickly dominated commercial and military flight in the 1930s, ultimately providing half the horsepower of American engines during World War II. Jack Connors explains how Pratt & Whitney came from behind the competition in developing gas turbines after the war with the debut of the J57, which powered the B-52 in 1952 and later the Air Force Century Series fighters (F-100, F-101, and F-102) and the Navy A-3D, F-4D, and F-8 airplanes. Also covered is the development of the J58, which powered the Mach 3+ YF-12 and SR-71 aircraft and subsequent military engines; the F100 in the F-15 and F-16; the F119 in the F-22; and, the F135 in the F-35 series. Pratt & Whitney's contribution to the luxury commercial jet era travel is also detailed, with its JT3, JT3D, JT4, JT8D, JT9D, PW2000, PW4000, and PW6000 in Boeing, Douglas, and Airbus aircraft. This history of Pratt & Whitney's role in the evolution of aircraft engines from 1925 to the present day offers young engineers a wealth of insights about design, development, marketing, and product support for commercial and military customers.