If you love colour in architecture..
I'm not so keen on Rossi's architecture as it seems a bit contrived and predictable now-a-days, intitially it was eye opening, but I love his use of colour.
Initially I was going to rate this book 4 stars as I find the format a little small but then again Its a personal thing and size is probably related to a publishing decision as I suspect this book would only have limited appeal despite it's cover. Anyway, I've given 5 stars for encouragement as any book on sketching, the guenuine creative part of the design process, gets my best vote.