Seventy years ago, cars and airplanes were still deathtraps waiting to happen; today, both are safer than ever, thanks in part to a pioneering Air Force doctor's research on seatbelts and ejection seats. John Paul Stapp (1910-1999) was once blasted—faster than a .45 caliber bullet—across the desert in his Sonic Wind rocket sled, only to be slammed to a stop in barely a second. At great personal risk, Stapp repeated the experiment many times until enough data on deceleration could be collected. From the legendary high-altitude balloon tests that ensued to the ferocious battles for car safety legislation, Stapp never stayed at rest, and Craig Ryan's biography of this Renaissance man also serves as a chronicle of America's transition into the Jet Age.