As long as human beings have inhabited the Earth, there have been individuals willing to risk their lives in order to discover and explore the unknown. Following in this great tradition, astronauts continue to push ever farther, into the frontier of space. The U.S. Space Camp Book of Astronauts highlights some of the outstanding men and women of space: Alan Shepard, Heil Armstrong, and other legends of the spacerace years Skylab commander Pete Conrad...