The book discusses the evolution of cellular technology, then focusing in on 5G and its architecture and what it means for current engineers. The book first focuses on 4G and how it changed the industry, allowing people to communicate by connecting devices to the internet. The authors detail the emergence of services and applications that have revolutionized communication and continue to impact the daily habits of majority of the world's population. The authors endeavor to tell this story by showing the path taken until the arrival of 5G, detailing how technological and architectural progress evolved in all these years. It is a technical book, but the authors take care to explain in detail each aspect related to technology in order to allow everyone interested in the subject to delve into this important topic. Presents a comprehensive explanation about 4G and 5G architecture, modulation and protocols; Includes a thorough explanation of modern antennas technology and O-RAN; Relevant to technology professionals and students interested in 5G, but with little background in telecommunications; The English translation of this book from its Portuguese original manuscript was done with the help of artificial intelligence (machine translation by the service provider DeepL.com). A subsequent human revision of the content was done by the author.