Drawing almost exclusively from primary sources, this volume details the development history of each of the many Westinghouse J40 engine models. Long buried in various archives, the technical struggles of Westinghouse to achieve success are at last revealed in detail. The J40 engine program occurred at a time when engine manufacturers the world over were endeavoring to push engine thrusts and efficiencies beyond the initial achievements in World War II and the years immediately following. Westinghouse failed to make timely investments in resources and research until it was too late to affect the outcome of the program. The failure of the higher powered J40 models that the U.S. Navy counted on for multiple airframe projects seriously delayed major programs, resulting in Congressional censure. Focusing on the technical aspects of the engines, this volume clarifies and corrects the many errors published over the years regarding these engines. The volume includes many informative illustrations and charts regarding the construction and operational details for the various models.