Jun'ichirō Tanizaki's masterful collection, 'The Key' and 'Diary of a Mad Old Man,' delves into the intricate and often dark aspects of human desire and the aging process. In 'The Key,' an aging professor and his wife use diaries to document their escalating sexual games, leading to a psychological unraveling. 'Diary of a Mad Old Man' presents an elderly man's struggle with physical decay while consumed by an erotic obsession for his daughter-in-law. Together, these novellas offer a profound, unsettling, and meticulously crafted exploration of taboo desires, decaying bodies, and the complex interplay between passion and infirmity, characteristic of Tanizaki's unique literary genius.