In 1895, a cultured, well-educated young German named Arnold Genthe arrived in San Francisco as a tutor to the son of an aristocratic family. Almost immediately, Genthe was attracted by Chinatown, or "Tangrenbu" a teeming ten-block area of crowded buildings, narrow streets, and exotic sights and sounds in the shadow of Nob Hill. Fascinated by a living culture totally foreign to his experience,…