This document discusses computer networks. It defines a network as a connection between two or more computing devices that allows them to share information. It describes three types of networks: local area networks covering small areas like a room, metropolitan area networks covering larger areas like a town, and wide area networks connecting geographically distant computers like the Internet. The document outlines some advantages of networks like faster communication and shared resources, and some disadvantages like spread of viruses and server failures. It also compares wired and wireless network configurations in terms of costs, speeds, and common components.