Some of today's most famous and successful aircraft were influenced by advanced technologies first tested and flown on European X-Planes. A significant number of aviation "firsts" occurred at secluded flight test facilities located in England, France, and Germany. The world's first jet airliner (1948), first jet transport with rear-mounted engines (1956), first VTOL jet fighter (1964), and first supersonic airliner (1969) were all developed in Europe utilizing technological advances pioneered by these rare and highly advanced X-Planes. Unpublished photographs, detailed appendix, and stories of these historic aircraft combine to produce an in-depth look at these secret aircraft.