Michael Kimsal has posted about the release of a new book from php|architect publishing, PHP Architect's Guide to Programming with Magento. Coincidently, one of the authors is also his brother Mark Kimsal.
I'm really excited for him, as I know he put a lot of work over the past several months learning Magento and writing the book. The biggest challenege was dealing with the underlying architecture changes that the Magento team applied in various versions leading up to (and including after!) the 1.0 release.
It's hard to hit a moving target like that, but as Michael mentions, the book and its authors did a great job of it.
The book as been officially released and can be purchased on the php|architect website in either a Print+PDF ($34.99 CAD) or just PDF ($29.99 CAD).