Who is Dr. Cornelia Wilbur from Sybil and what is their importance?

When Dr. Cornelia Wilbur first meets Sybil, she is a young psychiatrist. Sybil describes her as having a heart-shaped face, and even in the years between their first meeting and their reunion, Sybil notes that Dr. Wilbur remains as youthful as ever.

Dr. Wilbur is invested in Sybil's treatment, and she worries about how she will meet her patient's unique needs. Their separation proves to do them both a world of good. In the time Dr. Wilbur stops working with Sybil, she undertakes additional training and increases her patient interaction. Honing these additional tools better equips Dr. Wilbur to work effectively with Sybil after their reunion. Over time, she slowly begins to detect the different selves and seeks to treat each of them as well. Dr. Wilbur takes her time with Sybil and really petitions on her behalf. The relationship between patient and doctor transcends conventional client-doctor boundaries. The reader gets the sense that there is a substantial friendship that develops and which enables Sybil to work through her life history to integrate her selves.