_Along the way, we hope you have noticed some important guideposts—things like Newton’s law of gravitation, the law of reflection of light, the Stefan-Boltzmann law. They typify the basic principles of physics that engineers and scientists, whatever they do, must always keep in mind. No matter how exotic or up-to-the-minute the application, the ground rules of physics must be followed. If we have convinced you of this, we have done what we set out to do!_ Suggested Reading If you would like to read further about satellite communications in general or get some information about the case histories in Part II, you may be interested in using the following reading list. The references under each of the subheadings are listed chronologically; they include books, reports, technical papers, and magazine articles. As you can see, some of these ought to be understandable by almost anyone, but others are quite technical in nature. For further background in the basic physical principles that are discussed in Part II, you may refer to many good high school and college physics texts. An increasing number of useful physics books—both originals and reprints—are now being published in paperback form. Satellite Communications Arthur C. Clarke, “Extra-Terrestrial Relays—Can Rocket Stations Give World-Wide Radio Coverage?,” _Wireless World_, October 1945, page 305. John R. Pierce, “Orbital Radio Relays,” _Jet Propulsion_, April 1955, page 153. John R. Pierce and Rudolf Kompfner, “Transoceanic Communication by Means of Satellites,” _Proceedings of the I.R.E._, March 1959, page 372. John R. Pierce, “Exotic Radio Communications,” _Bell Laboratories Record_, September 1959, page 323. Steven M. Spencer, “Dial ‘S’ for Satellite,” _The Saturday Evening Post_, January 14, 1960, page 13. Space Electronics Issue, _Proceedings of the I.R.E._, April 1960. William Meckling, “Economic Potential of Communication Satellites,” _Science_, June 16, 1961, page 1885. Special Issue on Project Echo, _Bell System Technical Journal_, July 1961. C. C. Cutler, “Radio Communication by Means of Satellites,” _Planetary and Space Science Journal_, July 1961, page 254. W. C. Jakes, Jr., “Project Echo,” _Bell Laboratories Record_, September 1961, page 306. John R. Pierce, “Communication Satellites,” _Scientific American_, October 1961, page 90. United States Senate, Committee on Aeronautical and Space Sciences, _Communication Satellites: Technical, Economic, and International Developments_ (staff report), U. S. Government Printing Office, Washington, 1962. L. J. Carter, editor, _Communications Satellites_, Academic Press, New York and London, 1962. “Situation Report on Communications Satellites,” _Interavia_, June 1962, page 749. Leonard Jaffe, “Communications by Satellite,” _International Science and Technology_, August 1962, page 44.