The first chapter introduces the computing field, where a computer is a programmable electronic device that can process, store and retrieve data. It processes data according to a set of instructions (or program), and all computers consist of two basic parts namely hardware and software. There are two distinct families of computing devices namely digital computers and the historical analog computer. These two types of computer operate on quite different principles, and the earliest computers were analog. We discuss the von Neumann architecture, which is the fundamental architecture underlying a digital computer.