The book he mentions is the best book I've read about software architecture that will never be found in the Technical/Computer books section. I've given away at least five copies as Thank You gifts. The beauty of the book is that he presents such a convincing case for the importance of adaptability and a core architecture to enable that - that you start to view the codebase you are working on, heck, even your life through the perspective of: "what decisions am I making now that might impact the ability to change"