These two modern classics by the great Japanese novelist Junichiro Tanizaki, both utilize the diary form to explore the authority that love and sex have over all.
In The Key,
a middle-aged professor plies his wife of thirty years with any number of stimulants, from brandy to a handsome young lover, in order to reach new heights of pleasure. Their alternating diaries record their separate adventures, but whether for themselves or each other becomes the question. Diary of a Mad Old Man
records, with alternating humor and sadness, seventy-seven-year-old Utsugi's discovery that even his stroke-ravaged body still contains a raging libido, especially in the unwitting presence of his chic, mysterious daughter-in-law.