A long, fully caparisoned historical novel built around a rather obscure figure in the history of central-northern Europe, Johann Friedrich Struensee, who became prime minister and virtual dictator under the reign of the mad king of Denmark, Christian VII, to whom he first went as physician. He became the lover of the unhappy young queen, converted her malaise into abundant gaiety and health, as they rode together and spent many hours dedicated to love. Caroline Matilda boasted her passion, bore his daughter, while the king knew what was going on but was satisfied with his Negro boy and his dog, Bellerophon. The grasping courtiers, persuaded by the nobles whose power was disintegrating under Struensee's idealistic reforms, -- elimination of the privy council, establishment of public education, changes in the taxing systems, social benefits, etc. -- staged a palace revolution which brought death to Struensee. Even the people resented the changes that were raising them from their feudal state -- and backed the revolt. Struensee died as an adulterer, self-confessed. The queen was exiled and Juliana, queen-mother, came into power, and once again Denmark lay under the threat of Russia. The novel is in the tradition built to popularity by Costain and more recently by Phil Stong -- in the selection of an obscure character and a meticulously detailed setting. Maass seems, however, more wordy, slower motion -- and the book loses, rather than gains, by the frame in which he has set the story. His earlier books, of which Don Pedro and the Devil is best known, were all published by Bobbs- Merrill.