The first man-made satellite- to be launched next year in Florida- is now at varying stages of design, testing, manufacture, assemblage. What are the constituent parts? How do they function together? What mechanical failures are to be anticipated? How, imaginatively, will the take-off occur on the great day? What is the history of the satellite's development? What information do scientists seek from the ""peace-head"" of instruments racing five miles a second around the earth? Caidin has done all that a top scientific reporter can do to propound and answer these questions. He is as lucid and intense and questioning as the occasion demands, and sustains the same high technical standards of his Worlds in Space and Rockets and Missiles.