This work is intended for non-engineering industry professionals, students and anyone interested in learning the fundamental physical principles underlying the design of communications, devices and systems. This edition covers all the basic technological concepts of the principles behind modern communications systems. Beginning with first principles, it introduces the fundamental electrical and electronic definitions, and then builds upon them logically to cover more complex telecommunications concepts and computer-based systems. CD-ROM, quadrature amplitude modulation, and spread spectrum techniques used in current wireless technology, are covered in this edition.