This book explains the fundamental technologies and components used in modern processors and computer architectures and how varied architectural choices culminate in computer configurations that are optimal for certain applications. To put it nicely, modern computers are sophisticated gadgets. Nevertheless, when examined hierarchically, the roles of each degree of complexity become apparent. We will cover a large number of subjects in this book and will only be able to investigate each of them to a limited extent due to space constraints. Our objective is to present a comprehensive overview of each significant technology and subsystem found in a modern digital device and to explain how they interact with other system components.