This document provides an introduction to computer networks and IP addressing. It discusses the history of computer networks and the development of networking models like OSI and TCP/IP. IP addresses are unique addresses that allow devices to communicate on a network. The document describes the different classes of IP addresses (A, B, C, D, E) and how they divide the 32-bit address space. It also explains the concepts of network IDs, host IDs, subnet masks, and how subnetting can be used to logically divide a large network into smaller subnetworks.