CGI is the Common Gateway Interface which allows you to create Web pages on the fly based on information from buttons, checkboxes, text input and so on. The pages can be images, sounds, text and indeed everything else transferable by the Web. They can even be references to other Web pages. In this tutorial we concentrate on creating HTML documents (rather than images and sounds) but the principles transfer readily to other formats. This should provide a good start to cope with the more comprehensive documentation elsewhere.