This book provides and assesses the techniques required for the realization of practical wireless-powered backscatter systems for large-scale and intelligent IoT networks. It explores the deployment, reliability, and security aspects of backscatter devices for both indoor and outdoor environments. The book also sheds light on some of the recently evolving technologies such as artificial intelligence/ machine learning, non-orthogonal multiple access (NOMA), and multi-tone carrier techniques and identifies their application in backscatter communications. In addition, it offers a valuable blueprint for future studies in the domains of intelligent reflective surfaces, ambient backscatter communications and massive IoT networks.