Sybil is a 1973 book by Flora Rheta Schreiber about the treatment of Sybil Dorsett (a pseudonymfor Shirley Ardell Mason) for dissociative identity disorder (then referred to as multiple personality disorder) by her psychoanalyst, Cornelia B. Wilbur.
Mason is given the pseudonym "Sybil" by her therapist to protect her privacy. Originally in treatment for social anxiety and memory loss, after extended therapy involving amobarbital and hypnosis interviews, Sybil manifests sixteen personalities. Wilbur encouraged Sybil's various selves to communicate and reveal information about her life.
list of Sybil's "alters", together with the year in which each appeared to have dissociated from the central personality. The names of these selves were also changed to ensure privacy.
- Sybil Isabel Dorsett (1923), the main personality
- Victoria Antoinette Scharleau (1926), nicknamed Vicky, self-assured and sophisticated young French girl
- Peggy Lou Baldwin (1926), assertive, enthusiastic, and often angry
- Peggy Ann Baldwin (1926), a counterpart of Peggy Lou but more fearful than angry
- Mary Lucinda Saunders Dorsett (1933), a thoughtful, contemplative, and maternal homebody
- Marcia Lynn Dorsett (1927), an extremely emotional writer and painter
- Vanessa Gail Dorsett (1935), intensely dramatic
- Mike Dorsett (1928), one of Sybil's two male selves, a builder and a carpenter
- Sid Dorsett (1928), the second of Sybil's two male selves, a carpenter and a general handyman
- Nancy Lou Ann Baldwin (date undetermined), interested in politics as fulfillment of biblical prophecy and intensely afraid of Roman Catholics
- Sybil Ann Dorsett (1928), listless to the point of neurasthenia
- Ruthie Dorsett (date undetermined), a baby and one of the less developed selves
- Clara Dorsett (date undetermined), intensely religious and highly critical of Sybil
- Helen Dorsett (1929), intensely afraid but determined to achieve fulfillment
- Marjorie Dorsett (1928), serene, vivacious, and quick to laugh
- The Blonde (1946), a nameless perpetual teenager with an optimistic outlook