The situation could be a lot better, though. Apple doesn't have the institutional commitment to developer documentation that Microsoft does. Not one of Apple's current manuals, in my opinion, meets the standard of Amit's internals book. The Apple material is usually better grammatically, but communicates much less information in the same amount of space and usually with more ambiguity. In part, the ambiguity results from Apple not wanting to be tied to specific implementation details, where Amit's book is all about the implementation details. But it also results from bad -- or simply incomplete -- writing.

This is probably partly because Avie T. didn't believe in a separate documentation group; he thought engineers could write documentation. Most engineers, even ones capable of excellent writing, can't crawl out of their heads and empathize with someone who doesn't already know the technology. There are major exceptions, but they are very rare.