Since the release of the first NCSA Mosaic clients in 1993, the World-Wide Web (also known as the Web) has become an increasingly popular tool for disseminating information over the Internet. The HyperText Markup Language (HTML) is used to structure and format documents for presentation on the Web. HTML enhances ASCII files with markup tags that permit the display of a variety of fonts, images, and highlighting options; designate structural elements such as headers, lists, and paragraphs; and provide hypertext links to other documents on the Internet. This tutorial describes HTML tags, provides examples of their use, offers guidelines for organizing hypertext documents, suggests what types of documents are suitable for the Web, and explores the future of HTML.