The U.S. Air Force began developing jet fighters as World War II came to a close. The Cold War that soon developed saw a significant increase in fighter production programs as America tried to counter the perceived Soviet threat. World War II's best piston-powered fighters could barely top speeds in excess of 450 mph. But the post-war jets developed by the U.S. Air Force were soon breaking the sound barrier, flying to Mach 3, and Mach-4capable aircraft were on the drawing board. U.S. Air Force Prototype Jet Fighters details the evolution of these aircraft, using dozens of never-before-published photographs from government archives.