This book covers several essential aspects of pervasive ambient backscatter communication, one of the most cutting-edge technologies for Internet-of-Things. It begins with introductory Part I, which presents visions, basic concepts, principles, and paradigms of ambient backscatter. Also, a taxonomy of state-of-the-art ambient backscatter systems is provided from the perspective of the OSI model. Part II and III study how ambient backscatter systems work on the communication and networking levels.