The document discusses the history and functionality of web browsers, defining them as applications that retrieve and display content on the World Wide Web. It highlights significant milestones, such as the invention of the first web browser, World Wide Web (later Nexus) by Tim Berners-Lee in 1990, and the introduction of graphical browsers like Mosaic and Mozilla Firefox. The document compares various browsers, emphasizing features, advantages, and user interfaces of Mozilla Firefox and Internet Explorer.