Tadeusz Manteuffel
English, Polish translation I'm trying to learn more about Polish history, and this is a good starter, Focuses mainly on the politics, and various conflicts among competing princes, both externally with the Bohemians, the Empire, Hungarians, and Rus, but internally with the dynasty fracturing.
Can be dry and repetitive, but competently written by an expert on the topic, Polish historian, specializing in the medieval history of Europe,