We've just used this in our home educating environment, concentrating initially on 'Mosque' as we've been looking into Islam. Not really knowing anything before, we've been left fascinated with the details and thought involved - in the construction of the Mosque 'community'. The information is presented as if at that time; the drawings and details are very pleasing to the eye. Later in the spring-time we'll move onto 'Castle' which I'm confident will be equally as interesting.
I am reading it with my 3.5yo son - the text is way too advanced for him, but it makes it interesting for me, and he loves to study the drawings instead! It's a fine book, well researched and some drawings offer surprising perspectives, that actually reveal everything you ever wanted to know about those magnificent buildings...! And if you consider this book is actually three books in one, it is also a real bargain.