P. R. Stanley wrote:
Paul: I see my role as someone who is less likely to take anything for granted in regard to covering the basic principles.
That would be great, because it's always difficult for an author to write an explanation when he knows the subject too well. Unfortunately, it's equally difficult if he doesn't know the subject so well :) Don't hesitate to pinpoint poor explanations and such.
Paul: So, how do I start? I mean, do I need a username and password to gain access to the content?
No, you don't need to register with a username to edit pages. Having a username can be convenient though. The most useful feature is that you can define a "watchlist". At http://en.wikibooks.org/wiki/Special:Watchlist, the system then lists all pages from your watchlist whose content has been changed recently.
I've already located a few areas where I could introduce some improvement.
Just be bold and edit them :) Here's a short description on how to edit pages. To edit a page, follow the link with the title attribute "You can edit this page. Please use the preview button before saving. [e]". You can also restrict your edits to individual sections by following links whose title attributes start with "Edit section:". The text to be edited then appears inside a huge <textarea> inside a web form. The text is not written in HTML, it's "wiki markup" which is rather different. More explanations about the markup can be found on the page http://en.wikibooks.org/wiki/Help:Editing. After you're done editing the text, clicking the button with the title attribute "Save your changes [alt-s] [s]" will upload your new text to the wikibook server and be readable by everyone else. Every page (take for example http://en.wikibooks.org/wiki/Haskell/Variables_and_functions) also has an associated "talk page" (in this case http://en.wikibooks.org/wiki/Talk:Haskell/Variables_and_functions) that serves as a place for discussions and questions about the text. For instance, if something in the text is unclear but you don't know or don't have time to rewrite it, you can leave a message on the associated talk page.
BTW, I have an idea for including latex source code without disturbing the general composition of the text. How about using an img element for displaying a little symbol of some sort and, the alt attribute for containing the textual equivalent of the formula? The screen reader would display the alt text along with the so-called mainstream version but sighted users viewing the page in IE or Firefox would only see the graphic symbol. It could be anything - a little circle or a custom symbol to denote the accessibility feature.
Wikibooks (and the other wikimedia projects) even transform every LaTeX-formula into an image, so that sighted people see the formula. An example is the image with the alt text "h = f \circ g" from the page http://en.wikibooks.org/wiki/Haskell/Category_theory. The alt text is the LaTeX source from which the image is generated. Regards, apfelmus