During World War II, America's air arms fielded some superlative fighters such as the Republic P-47 Thunderbolt, North American P-51 Mustang and Vought F4U Corsair. The large numbers of these excellent fighters produced by the US aircraft industry made a significant contribution to the eventual success of the Allies. However, even as the war was raging and the industry was working flat out to produce the huge numbers of aircraft required for front line duties, extensive research and development programmes were also being pursued to create the next generation of fighters. This book focuses on the aircraft generated by those programmes and provides a detailed survey of the fighter prototypes produced and flown during the period from 1940 to 1946, which, for various reasons, did not progress to production and service. The work has twenty-four chapters that embrace the great diversity of design and layout of these prototypes. They demonstrate the remarkable creative flair that was present in the US aircraft industry during the war. There are designs of all shapes, sizes and configurations powered by piston, jet and mixed power plants. The designs encompassed various configurations including pusher layouts, swept and flying wings. Each of these prototypes is given its own chapter. The book also reviews a selection of production fighter types that were kitted out for trials and used as test bed aircraft. A small number of unbuilt projects and studies are also included. The thoroughly researched text is complimented by a superb collection of photographs and illustrations. For all of those interested in World War Two US aviation and the aircraft produced in its aftermath, this book will be a revelation. Written by Tony Buttler, one of our most distinguished aviation writers, it will be a must read for all modellers and students of aviation history in this era.