The Bird's Nest — Shirley Jackson

Elizabeth is a demure twenty-three-year-old wiling her life away at a dull museum job, living with her neurotic aunt, and subsisting off her dead mother's inheritance. When Elizabeth begins to suffer terrible migraines and backaches, her aunt takes her to the doctor, then to a psychiatrist. But slowly, and with Jackson's characteristic chill, we learn that Elizabeth is not just one girl, but four separate, self-destructive personalities. The Bird's Nest, Jackson's third novel, develops hallmarks of the horror master's most unsettling work: tormented heroines, riveting familial mysteries, and a disquieting vision inside the human mind.