High Quality Content by WIKIPEDIA articles! 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),. Marketed as part of the author`s Time Quintet (the other four volumes of which are called the Time Quartet), An Acceptable Time connects Polly`s adventures with those of her parents, Meg Murry and Calvin O`Keefe, which take place a generation earlier. The book`s title is taken from Psalm 69:13, "But as for me, my prayer is to You, O Lord, at an acceptable time."