Today we stand on the threshold of human flights to Mars--yet another giant leap from that one small step onto the moon. But Neil Armstrong and Sally Ride would have never made history, and humankind would not have touched the stars, if not for the men and women on the ground who lit the fuse that launched the first rockets. Enthralled as a boy by the exploits of Flash Gordon and the novels of Robert Heinlein and Arthur C. Clarke--who put the science...