Quick review of Dan Roam's The Back of the Napkin, which I've just finished. It is an excellent guide to visual thinking in business, and a passionate call to arms to get back to the brass tacks of marker on whiteboard or biro on napkin.
It is certainly a must-read book but, for reasons I can't quite articulate, I found it strangely disappointing. Perhaps I expected it to revolutionise the way I see the world, and was sad to find it merely good.
Don't let me put you off though, it is a very useful book. I particularly liked Roam's comprehensive "visual thinking codex", which you can download from the website (though it probably won't make much sense on its own). This offers a complete palette of visual solutions, categorised by problem and offering a selection of versions for different audiences.