In order to better understand the section 8.8, it is useful to know a little bit about CGI and the HTTP protocol.
The HyperText Transfer Protocol (HTTP) defines communication by a client and a WWW server. It is the ``backbone'' of the Web.
The Common Gateway Interface (CGI) is a tool for creating interactive Web sites. It allows you to send user data from a client to the server. The server then can processes the data and send back some feedback, usually in the form of dynamically created HTML. On traditional Web servers like NCSAs this is done by calling scripts (programs) that sit in some special cgi directory and to which the user data is passed for processing.
On the WWW you can find several good HTTP/CGI tutorials, e.g. Dave's CGI Tutorials, Michael Grobes Instantaneous Introduction to CGI Scripts and HTML Forms. You also might want to look at the official HTTP 1.0 spec and the CGI Spec at NCSA. Or just start surfing at Yahoo's Top:Computers and Internet:Internet:World Wide Web
Let's first look at HTTP and how it is being used by E_Web.