1. Did you have to 'kick back' any money? To those that you interviewed, or companies where you used their screenshots in your examples/critiques? Did you reach out to them and notifying them that they/their company will be in your book for profit?
2. From the sample chapter, you talk a lot about principles and critiques of interface design but are there any area in the book where there are data or user ability studies to explain it further (ie: why they work)? Or is most of it based on experience?
3. Any plans for a sample page on the case study? I think that's where the most value is - the full process of where you take us through your thoughts and reasoning on designing a product.