The document defines and discusses different types of computer networks. It begins by defining a computer network as an interconnection of two or more computers that allows them to communicate and share resources. It then discusses the basic components of a network like computers, cables, network cards, and software. The document classifies networks based on their geographical area into local area networks (LANs), wide area networks (WANs), personal area networks (PANs), and metropolitan area networks (MANs). It provides examples of each type of network and how they differ based on their size and connection method.