This book is intended to give nonspecialists a readable survey of a difficult subject. Like its companion book, it also assumes no prior knowledge of telecommunications law or technology and avoids jargon wherever possible. We have tried to make this book useful to a wide range of readers, and in doing so we probably have not achieved any individual's ideal. So, for example, attorneys who practice telecommunications law may find the relative paucity of legal citations distracting, and engineers will certainly find our technical descriptions unilluminating; while those who specialize in neither field may think we have indulged too much in legalese, finds something of value here that was not readily available elsewhere. Each of us owea a debt to those who have helped with this project or tolerate us while we worked on it. We name only a few of them here.