Want to learn about the Internet but not sure where to start? This accessible guide offers a crash course on every topic you need to know to get up to speed with the modern Internet, balancing theory and application. Following a brief history of the Internet, you'll learn the basics of computer networking before diving into major topics like security, blockchain, and the Internet of Things. Particular focus is given to contemporary technologies like 5G, Wi-Fi 6, and decentralized computing. A perfect first book for beginners and a succinct reference for professionals, this is a no-nonsense, "nothing you don't need" guide to the world's biggest computer network.