ABC of Architecture
It's a non-technical discussion of the architectural triangle. The three sides of that triangle are function, structure, and beauty, which might sound boring as hell but trust me, it's not. I got a LOT of insight from this book, and I'll bet you will too. This is the sort of book that can give the heating professional an edge when going after those high-end jobs. The more you know, the better you look. Check it out.