The book focuses on the advanced mmWave/Sub-terahertz ultra-massive MIMO wireless communications, which are regarded as a promising paradigm shift in future 5G beyond and even 6G. This is achieved by providing a comprehensive review of the rapidly developing field of massive MIMO communication, in-depth discussions on the impact of extremely large-scale antenna array, and detailed numerical simulation results on our proposed schemes. Several case studies are given after introducing basic c...