Sei Shōnagon (清少納言, c. 966–1025) was a Japanese court lady and writer during the Heian period (circa 966–1017). Serving Empress Teishi, she gained fame for 'The Pillow Book', a witty, observational diary blending essays, lists, and anecdotes. Her work offers rich insight into court life and aesthetics of the time. Although little is known about her later life, she remains celebrated for her literary style and sharp, often humorous, commentary.