The biography of a woman, not the history of a reign. Massie defines Catherine by her lovers and I got tired of the revolving door to her bedroom. As for the queen, she's in favor of the Enlightenment only so far as it doesn't threaten her throne, and then it's censorship and slamming the door to the West. As a mother, she never perceived her son and heir as anything but a rival. If you want to rule a hereditary monarchy, you have to accept the inevitability of your own mortality and plan for the health and longevity of the institution you head. But monarchs almost never do, and Catherine was no exception.
In short, a complicated woman, intellectually superior to everyone around her yet bereft without a warm body in her bed, ambitious enough to accept if not connive at the assassination of her deposed husband to secure her place on the throne, and then forgiving enough enough to stand as godmother to his mistress's daughter. It's an interesting read, a good story told well, but it feels a little lightweight.