Canon John Tallis is a major character in the young adult novels of Madeleine L'Engle, appearing in four books. The character is based on L'Engle's real-life spiritual advisor, Canon Edward Nason West of the Cathedral of St. John the Divine in New York City.
Madeline wrote her books based off of other's experiences in real life.
It is not known what she used as inspiration for her books besides her own.