In the summer of 1911, the German writer Thomas Mann visited Venice in the company of his wife Katia. There, in the Grand Hotel des Bains, as he waited for the dinner-gong to ring, the author's roving eye was drawn to a nearby Polish family, the Moeses, consisting of a mother, three daughters, and a young sailor-suited son who, to Mann, exuded an almost supernatural beauty and grace. Inspired by this glancing encounter with the luminous child, Mann...