Way back in December, our Christmas Gift Guide featured our pick of the many OS X-related books out there. One of the recommendations was the (very excellent) Cocoa Programming for Mac OS X by Aaron Hillegass - commonly referred to as 'The Bible' in the Mac development community.
At the time the book was a little outdated -- however in the last couple of weeks an updated third edition has been published. New sections feature Objective-C 2.0, Core Data, Garbage Collection, Xcode 3 and Core Animation, meaning this third edition is all ready for many of the new technologies in Mac OS X Leopard.
At just $32 (via Amazon.com), this updated version clearly ought to be on every developer's bookshelf (and aspiring developer's wishlist).