For those interested in the handbook project that is just now getting off the ground, I highly encourage you to check out this latest post by Jane Wells on the WP Docs mailing list. A post about this will be published on the WordPress Dev blog in the near future.
http://lists.automattic.com/pipermail/wp-docs/2009-August/002034.html
Category: WordPress
That was a good read. It will be interesting to see the end result.
Hopefully they will include some sort of theming capability to the handbooks since reading the inspiration source (http://svnbook.red-bean.com) is difficult I think. Hard to overview also.