The Prussian king Frederick II (1712–1786) is perhaps best known for successfully defending his tiny country against the three great European powers of France, Austria, and Russia during the Seven Years’ War (1756–1763), a feat that allowed Great Britain to limit its engagement on the Continent and emerge as the world’s leading colonial power, as summed up in William Pitt’s famous claim that “America was won in Germany.”

But in his youth, tormented by a spectacularly cruel and dyspeptic father, this future military genius was drawn first to the flute and French poetry, and throughout his long life counted nothing more important than the company of good friends and great wits. This was especially evident in his longstanding, loving, and vexing relationship with Voltaire. An absolute ruler allergic to pomp, a nonhunter who wore no spurs, a reformer of great zeal who maintained complete freedom of the press and religion and cleaned up his country’s courts, a fiscal conservative and patron of the arts, the builder of the rococo palace Sanssouci and improver of the farmers’ lot, maddening to his rivals but beloved by nearly everyone he met, Frederick was—notwithstanding a penchant for merciless teasing—arguably the most humane of enlightened despots.

In Frederick the Great, a richly entertaining biography of one of the eighteenth century’s most fascinating figures, Nancy Mitford’s trademark wit and charm find the ideal subject.