The Harper Hall trilogy comprises three fantasy or science fiction novels by the American-Irish author Anne McCaffrey.They are part of the Dragonriders of Pern series as it is known today, 24 books by Anne or her son Todd McCaffrey as of summer 2011.In their own time, however, they were new Pern stories published by Atheneum Books in 1976, 1977, and 1979, alongside the Dragonriders of Pern series whose continuation in a third book from Ballantine was eagerly awaited until 1978.