A competent book, exclusively on the satellite aspect of the U.S. space program. To an even greater extent than many of our other space books, this one is parochial; there is no indication of any kind that the U.S.S.R. has ever launched a satellite. Like other writers on space science, Carlisle appears to rely on the inherent interest of the topic, not troubling to make the basic presentation more interesting; often the text reads like a series of captions for the many photographs. Yet in terms of information, it is both up to date (obviously important in this sort of book) and comprehensive on an elementary level. The organization is based on the functions satellites carry out or will carry out: communication, weather and environmental study, guidance systems, finding and protecting natural resources, mapping the earth, and exploring space. References to events in 1970 are frequent. Ross, in Space Science and You (1970) covers most of the same material and includes many of the same photographs. He writes at a slightly higher level, presenting more by way of historical context and how satellites work. The major area in which Carlisle supplies information which Ross does not is in astronomical observations from space.