As a British woman living in Beijing (then Peking) during the 1950s, Nan Brake was something of an outlier. The majority of foreigners in the capital were Soviets: scientists and technicians dispatched to help the fledgling People’s Republic of China. Brake, a Spanish and Mandarin speaker who had earned her Communist stripes in the Spanish Civil War, was there as a translator, working on English-language publications and subtitling films. But although Brake spent the best part of a decade committed to contributing to a new and industrializing China, she had an eye for its Imperial past. She met artists, craftspeople, and dealers on excursions across Beijing (or “junking trips,” as she called them), acquiring Ming dynasty paintings, embroidered Qing garments, and jade ornaments, all of which she had ferried back to London by 1960. Not that Brake’s descendants knew their worth. Until a recent visit by an antiquities specialist, the collection had spent four decades locked in a chest.…