The preface of the book emphasizes the importance of simplifying proof methods in advancing knowledge and preparing for further progress. It highlights three timeless truths in wireless communications: increasing demand for throughput, limited electromagnetic spectrum, and the need for higher spectral efficiency. The central thesis is that Massive MIMO represents a breakthrough technology, enabling large-scale, simultaneous communication across the entire frequency spectrum. This technology leverages an excess of service antennas compared to active terminals and uses measured propagation characteristics for multiplexing and demultiplexing, which simplifies signal processing and reduces radiated power. The book argues that despite the complexity of Massive MIMO systems, closed-form performance expressions can be derived using simple assumptions and elementary mathematical techniques. These expressions provide valuable insights into system behavior, scalability, and performance evaluation. The book is designed to appeal to wireless engineers, researchers, and students, offering a clear exposition of Massive MIMO principles and practical tools for system design and performance analysis.The preface of the book emphasizes the importance of simplifying proof methods in advancing knowledge and preparing for further progress. It highlights three timeless truths in wireless communications: increasing demand for throughput, limited electromagnetic spectrum, and the need for higher spectral efficiency. The central thesis is that Massive MIMO represents a breakthrough technology, enabling large-scale, simultaneous communication across the entire frequency spectrum. This technology leverages an excess of service antennas compared to active terminals and uses measured propagation characteristics for multiplexing and demultiplexing, which simplifies signal processing and reduces radiated power. The book argues that despite the complexity of Massive MIMO systems, closed-form performance expressions can be derived using simple assumptions and elementary mathematical techniques. These expressions provide valuable insights into system behavior, scalability, and performance evaluation. The book is designed to appeal to wireless engineers, researchers, and students, offering a clear exposition of Massive MIMO principles and practical tools for system design and performance analysis.