Probably my favorite photography book that I own, and the first one I ever got. I remember I found it in a bookstore while shopping with my dad, and he said I could get it as long as he didn't have to carry it, so I logged it around half of Oslo for about four hours. Totally worth it.
What I love about this book is all the sketches and moodboards, as you get a glimpse into Walkers creative process. It's filled with simply amazing pictures.
As all the other photography books I've shown, this would also be a really nice coffee table book, though perhaps a tiny bit big.
You can get this book at The Book Depository, or at a bookstore with a good photography section.