Book excerpt: This book focuses on cellular Vehicle-to-Everything (C-V2X), currently the most promising wireless communication technology for Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), Vehicle-to-Pedestrian (V2P), Vehicle-to-Network (V2N) and Vehicle-to-Cloud (V2C) communications. Because of its low latency and high reliability, C-V2X has become an essential enabling technology for Intelligent Transportation Systems (ITSs) and autonomous driving. This book begins by introducing readers to the research background and status quo of global development. Then, after analyzing the performance requirements of various V2X applications, the system architecture and technical standards are presented. The two evolving stages of C-V2X, i.e., LTE-V2X and NR-V2X, are introduced in detail. In addition, related technologies such as mobile edge computing, network slicing and high-precision positioning, C-V2X security, C-V2X spectrum requirements and planning, and industrial development and applications are introduced. In closing, the book discusses future applications of and technical challenges for C-V2X. This book is the first monograph dedicated to C-V2X, offering experts, researchers and engineers from the areas of IT/CT, intelligent transportation, intelligent and connected vehicles (ICVs) an in-depth understanding of C-V2X technology and standards, while also outlining related interdisciplinary research. The book can also be used as a reference resource for both undergraduate and graduate studies.