“Adobe’s Portable Document Format (pdf) is a translation format used primarily for distributing files across a network, or on a web site. Files with a .pdf extension have been created in another application and then translated into .pdf files so they can be viewed by anyone — regardless of platform*”. These documents tend to be difficult to read with adaptive technology products.
Adobe’s newest reader is version 11. Adobe maintains a site with information about Acrobat Accessibility at http://access.adobe.com. For more information on reading PDF files, check the Adobe 11 Accessibility page on Adobe’s web site.