An overview of the work of one of the world's best-known scientist-communicators. From Sagan's Brooklyn beginnings to his present protests against nuclear testing, Cohen uses his well-known readable style to follow the professional journey Sagan has traveled rather than his personal odysseys. Here was a boy fascinated with the stars, who read Edgar Rice Burroughs not for his Tarzan stories but for his tales of John Carter, visitor to Mars. Included are his education at the University of Chicago, his role in the Voyager, Viking, and Mariner expeditions, and his imaginative idea to send a scientific message on Pioneer 10, the first man-made object to leave the solar system. There's a humorous story of a spy trying to pry information from Sagan, and some commentary about this highly accomplished astronomer, who has gained enough fame on TV to spawn impressions of his voice. A mostly admiring portrait, Cohen gingerly acknowledges the troubles arising from Sagan's outspoken forcefulness. Personal interaction is limited; Sagan's three wives, sons, and daughter appear only briefly at the end. Potential astronomers and media buffs will enjoy reading about the man whose work asks us ""to consider ourselves in cosmic perspective.