Dear Elisa,
The book covers several tsars but focusses in Nicholas´time. There´s not much information on the Empresses, but there are a couple of anecdotes and the kind of first hand comments that you could like. Most of the material deals with their life in the corps des pages, and they pay a lot of attention to uniforms and military. Anyway, Many of the most interesting information, once you already own Virubova´s, Dehn´s, etc,etc... comes from this kind of books.
Definitely, i would highly recommend it.