This document provides an overview of e-commerce, including its definition, history, categories, benefits, and applications. E-commerce is defined as the process of buying, selling, transferring, or exchanging products, services, and information via electronic networks and computers. The history section outlines the evolution of e-commerce from the 1970s with the advent of technologies like EDI, through growth in the 1980s-90s with credit cards and the internet, to widespread online commerce today. Major e-commerce categories are business-to-consumer, business-to-business, with other models like consumer-to-consumer and mobile commerce. Benefits of e-commerce are also summarized.