I had checked out a book from the local library and liked it so much I came on amazon to buy that book, Fodor's Rome's 25 Best, 6th Edition (25 Best). Amazon then recommended this book to me and after looking it over decided to give it a try.
My wife and I went on a 12 day cruise of the Med and ended that we 3 days in Rome right before Thanksgiving 2006 (Nov. 2006). This book more than paid for itself with all of the helpful reviews in it and suggestions. But the topper for me was the quality and size of the maps. We looked enough like tourists in the city, but this little book and it's fold out maps helped us look a little less so. They were more than details enough, and having suggestions on them we found a wonderful place to eat one night, it was great.
If you want something that is small and compact, yet still provides great details in terms of maps of a city this is the book for you. And there is no huge map to fold and unfold as you walk around a city. This book breaks the city in to sections and based on where you are you have only a small map to easily unfold and use.
I highly recommend this book.