Exotic research aircraft designed, built, and flown in Europe in the two decades following World War II were the foreign equivalent of the legendary American X-Planes. Many of these advanced aircraft flown by test pilots such as Peter Twiss and Andre Turcat captured speed and altitude records previously held by their American counterparts.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 Unpublished photographs, detailed appendix, and stories of these historic aircraft combine to produce an in-depth look at these secret aircraft.