Hall's books usually feature independent, strong-minded young women.

Part of the appeal of the books comes from following the protagonists' increasing competence in coping with life's problems. The books subtly suggest to young readers that they cannot only learn to cope with adult problems but that they can even triumph over the problems, turning each step in acquiring self-sufficiency into a victory in the process of learning to control one's destiny. The Solitary is an excellent example of how Hall's main characters mature by fulfilling responsibilities.