This book provides a comprehensive coverage of reconfigurable intelligent surface (RIS) based wireless communications by covering all the technology stages from working principles, theories and algorithms, system architectures, real-world implementations, and programming platforms through performance measurements and system testing. Metasurfaces for Wireless Communications: Designs and Implementations serves as a must-be read for everything related to the use of RIS in wireless networks. Authored by three experts in the field, the book is organized into five in-depth and well-designed chapters. The first chapter discusses the fundamentals of metasurfaces for wireless communications as well as the related evolution and requirements of RIS in 6G. The second chapter is devoted to the modeling and analyses of RIS for wireless communications by including electromagnetic field modeling and theoretical analyses of both large- and small-scale channel models. In Chapter 3, the authors mainly address properties’ characterizations and system design of metasurface devices. Chapter 4 examines relay and system implementations of RIS for wireless communications through basic system models, key design aspects, and system simulations and architectures. Chapter 5 discusses the standardization of RIS-aided wireless communications by providing an overview of the relay technologies, field trials, and roadmaps in 3GPP standardizations.This book serves not only as a comprehensive reference for professional engineers, researchers, manufacturers, network operators, software developers, service providers, and regulatory bodies aiming at the development, standardization, deployment, and applications of B5G and 6G mobile communications, but also as a textbook for graduate students in circuits, signal processing, wireless communications, information theory, microwave technology, and antenna and propagation.