 Crossover characters Canon Tallis (who was responsible for Polly's unusual first name), Zachary Gray, and Adam Eddington (who met "Poly" in "The Arm of the Starfish") connect the Polly O'Keefe books to Madeleine L'Engle's series about the Austin family.In "An Acceptable Time", Zachary makes specific reference to his desertion of Vicky Austin at the end of "A Ring of Endless Light".