What is the series that XXX is a part of?
An Acceptable Time
An Acceptable Time is a 1989 young adult science fiction novel by Madeleine L'Engle, the last of her books to feature Polyhymnia O'Keefe, better known as Poly (The Arm of the Starfish, Dragons in the Waters) or Polly (A House Like a Lotus, An Acceptable Time).