I bought this book in English during my visit to St. Petersburg. As far as I know, it is sold only in the Palace. I really don't remember the price anymore, but it couldn't have been more than 500 roubles. Probably it was less!
As it was said, it is informative. If you aren't a really big fan of this family, you will be probably bored. There are almost no photos of the family. You read information about the heating system, toilets, cooking... If you are really interested in some of these topics, I can send you some info from the book.