ost abstract sense, we build web pages so that computers can read them. The software that people use to access web pages is what "reads" the document. How the page is rendered depends on the type of software being used. A visual browser such as Netscape or Safari will render pages with images and complex layouts. A text-only browser such as Lynx will render only the text and minimal formatting. A talking browser like Home Page Reader speaks the contents of a web page. There are other types of software that read web pages: email harvesting programs read web pages to extract email addresses; search engine software reads pages to place them in a web page catalog. When considered in the broadest sense, our primary audience is computers. Our web pages must be usable by computers. Of course, people use computers, and as we work our way from the general to the specific we are concerned with two types of users: visual and non-visual. Visual users are those who use the web by viewing ...