While Wikipedia is the standard reference for what wikis can do, its newer cousin Wikibooks is, in many respects, a more daring venture. This is a collection of open-content textbooks - that is, modules freely available to and updatable by anyone, covering a wide range of subjects. (General FAQs here)

Material on Wikibooks is searchable by bookshelves, by category, and, most quaintly, by Dewey Decimal System.

The site claims to offer almost 11,000 books by now - all editable by anyone, and none hostage to the infamous pricing practices of textbook vendors. A cursory tour today yielded many more placeholders than actual textbooks, but the venture is only two years old.

The September Wikibook of the month is rich and impressive, however, and though it’s a computer programming text, it’s also of sentimental interest to this renegade Byronist: Ada Programming.

Ada! sole daughter of my house and heart …. (CHP III.1)