Light and Dark, Natsume Soseki's longest novel and masterpiece, although unfinished, is a minutely observed study of haute-bourgeois manners on the eve of World War I. It is also a psychological portrait of a new marriage that achieves a depth and exactitude of character revelation that had no precedent in Japan at the time of its publication and has not been equaled since. With Light and Dark, Soseki invented the modern Japanese novel.

Recovering in a clinic following surgery, thirty-year-old Tsuda Yoshio receives visits from a procession of intimates: his coquettish young...