sentences:  They were published by Atheneum Books in 1976, 1977, and 1979, alongside the "Dragonriders of Pern" series.Omnibus editions of the two trilogies were published by the Doubleday Science Fiction Book Club in 1978 and 1984, titled "The Dragonriders of Pern" and "The Harper Hall of Pern" respectively.Harper Hall's target was young adults
  in contrast to the general audience for fantasy and science fiction.