Ziemer and Tranter provide a thorough treatment of the principles of communications at the physical layer suitable for college seniors, beginning graduate students, and practicing engineers. This is accomplished by providing overviews of the necessary background in signal, system, probability, and random process theory required for the analog and digital communications topics covered in the book. In addition to stressing fundamental concepts, sections on currently important areas such as spread spectrum, cellular communications, and orthogonal frequency-division multiplexing are provided. While the book is aimed at a two-semester course, more than enough material is provided for structuring courses according to the needs of the students and the preferences of the instructor.