The Winter Palace by Eva Stachniak (fiction)

This book about Catherine the Great's path to power, told through the eyes of a lady in waiting who served as a spy, was well written and fast paced.  It mostly focused on the spy lady's story, which I thought was a good way to get at details of Catherine's early life in Russia without having to make major leaps of faith.  There are a whole lot of salacious and damning stories about Catherine out there, and this book justifies some of her actions without tedious explanation, just good storytelling.  5-star historical fiction.