This document provides an introduction to computer networks. It discusses that computer networks connect autonomous computers that can be located anywhere geographically. It describes different types of networks including LAN, MAN, and WAN. Computer networks allow for resource and information sharing, communication, and distributed processing. The document discusses different network topologies such as bus, star, tree, ring, and mesh. It also covers network components like physical media, interconnecting devices, computers, networking software, and applications that run on networks. TCP/IP is described as the main networking protocol. Examples of applications that use computer networks are also provided.