Open-source book technology allows users to contribute to and edit an online volume. Wikipedia (http://en.wikipedia.org), the prototypical open-source site, hosts a free online encyclopedia.
Giles1 in 2005 found the accuracy of science entries in Wikipedia comparable to similar entries in Encyclopaedia Britannica. Among 42 entries from both encyclopedias, researchers found on average 4 errors per entry with Wikipedia and 3 with Encyclopaedia Britannica.
One sister Wiki project, Wikibooks (http://en.wikibooks.org), is designed to encourage production of open-source textbooks. This has led to one fledgling psychiatry textbook (http://en.wikibooks.org/wiki/Psychiatry) and others soon could follow. The clinical accuracy of this Wiki-based psychiatry textbook is variable, though this could improve if more psychiatrists become involved with Wikibook peer review.