This book has major flaws as a guidebook. It is relatively rich in informaiton and interesting as a read if you want to know about Rome and useful if it is used as a referrence alongside other guidebook (which is what we did in the end), but if you want to walk around the city with this book in hand, you can hardly find what you want to see and figure out where you are and what it is in front of you.
Because in places like Rome you have all sorts of historic things lying about all over, you need one, a useful guide how you can go about without missing "must sees" (model course with good map and good instructions), two, a clue/instruction how to recognise something important and not to go past it without realising what it is - many ruins and churches look similar if you don't know them (again good map that can be easily referred back to entries of the text), and three, you want to know what it is when you came across something interesting while roaming around the city. This book was no help in any case. Imagine - if you come across something interesting which has no tags saying what it is, which is often the case in Rome, especially where there are so many ruins in proximity, you have to determine either from your location (good map is needed) or marker (what is near-by). Neither of them is provided in the guidebook. Everytime we came across a church or ruins that looked interesting (some of them really famous), we had to spend quite a long time trying to figure out where we were and what it was, sometimes in vain (maps unclear and complicated, the text just listed items with no indication where are they, how to find them etc.) Later we realised that we had missed out some of the must-sees even though we visited places nearby because there are no clue on what we can see if we are in a particular place and the maps were quite useless. Also, in some occasions we actually saw a wrong thing believing it was what we wanted to see, to be later surprised to come across the real thing (again poor map and lack of a marker and proper guide) or just passed across something without realising what it was.
We also found some of the information on restaurants were outdated. Once we entered this highly recommended restaurant, which was flooded with tourists and food was really bad (I had very very dry, hard steak - I could not believe it, as although I am not a big meat eater, I find meat dishes in Italy usually wonderful). The service was pretty bad too (sort of "be greatful we are feeding you" attitude). When we asked for a bill the server (I think he was owner as well) dared to say that "Service cahrge is not included", demanding for tips. We left without paying any tip, greatly regretting we missed one precious meal in Rome and relearning a great lesson - if there are a lot of tourists and no locals, just walk away.
Having said this, with more thoughts into how to make things more clear, I think it can be turned into a good guidebook. Improved quality of the maps (and probably more maps to highlight important areas), which can be easily referred back to the text and vice versa, and reworking structure of the text and giving more instructions/markers where and how to find monuments will be absolutely necessary. But if you're looking for a propper guidebook to take you through Rome, you better wait for a revised edition or get something else.