I'm only into the second chapter, and I just had to say - fantastic book!Most of the books out there tend to be just API references, but to have this kind of stuff down on "paper" in a coherent manner is extremely useful.Have you ever thought about writing a full length, in depth book?
By December, it's due out by the first week of August (gasp!) Here's the book on Amazon, note that the title isn't final
One of the things I liked about Karl's book is that he teaches you not just how to build software but how to build better software.