On the one hand, any book/historical atlas that covers Russia is a good thing, since this huge, historically important country tends to be slighted in English books -- although the situation seems to be improving some. This entry in the Penguin Historical Atlas series is thus helpful by graphically showing the development and growth of the Russian state.
That said, this is one of the poorer entries in the series. The editing on my copy is poor, the repetition between the section introductions and the individual map-accompanying text is pretty awful, and the maps themselves are not organized particularly well -- often hopping back and forth over large, important stretches of time. I gave it three stars because it's still a helpful starting point, but not much more than that.