When eight divisions of North Korean troops slammed through the 38th Parallel on June 25, 1950, it heralded a battle for air superiority of unprecedented scope; it also unleashed a new age of aviation fighting technology. A first generation of jet fighters from the Soviet Union shot it out with America's finest, as Migs and Sabres tussled high in the skies over Asia. Meanwhile, older piston-powered warbirds with roots in World War II duked it out in the contours of the hills below Robert Jackson captures the story of cold precision that turned 30-year-old-fighter aces from the piston age into a new breed of jet aces.