The North American XB-70 Valkyrie was an attempt to build the ultimate offensive weapon fo the Cold War - a heavy bomber capable of flying at Mach 3 and reaching targets deep inside the Soviet Union. The aircraft that emerged was one of the most graceful large aircraft ever to fly, and one that looked everybit as fast on the ground as it ws in the air - over 2,00 mph at high altitude. It was years ahead of its time. But politics and changing requirements ultimately doomed the Valkyrie program to only two aircraft. Neighter was a true prototype of a weapons system, and instead was used to test the concept of such a large aircraft flying so fast.The authors have uncovered a great deal of new matierial on the XB-70 program - both on the aircraft as flown, and on what the proposed production aircraft would have looked like had they been built. Many never-before-seen photographs and drawings are included in the book. Details of the defensive perspective with the politics and economic realities that caused its cancellation.