During the years preceding and during WW2, the RAF and the Royal Aircraft Establishment were responsible for the selection and procurement of British military aircraft and also to evaluate their capabilities against captured enemy models whenever possible. During the lend-lease agreement with the USA, the RAF and Fleet Air Arm operated several American designs, each of which was tested to evaluate its potential.This book looks at the key area of fighter aircraft and includes the test results and pilot's own first-hand accounts of flying seventeen different models, designed in the UK, America and Germany. The reader will learn of the possibilities of air superiority offered by these types and also their weaknesses. Types included are The Hawker Hurricane, Supermarine Spitfire, Boulton Paul Defiant, Hawker Tempest and Typhoon, Bell Airacobra, Messerschmitt Bf 109, Focke-Wulf Fw 190, Brewster Buffalo, Curtiss Tomahawk, North American Mustang, Grumman Martlet, Republic Thunderbolt, and Vought Corsair. All aircraft that saw a great deal of action throughout the War and which are now part of legend.