In 1920, young Olga Chekhova, the beautiful niece of Russian playwright Anton Chekhov, fled Moscow for Berlin?taking only a smuggled diamond ring. Olga quickly won both celebrity as an actress and prominence in the ranks of Germany?s Nazi party, eventually becoming Hitler?s favorite actress. But was she really a sleeper agent recruited by her brother, Lev Knipper, to spy for the Russian NKVD?Antony Beevor?s The Mystery of Olga Chekhovatells the extraordinary...