Armchair Fiction presents extra large editions of classic science fiction double novels. The first novel is "The Secret Kingdom" by Otis Adelbert Kline and Allen S. Kline. Deep in a South American mountain hideaway was a secret kingdom of lost Indians, descended from a race once conquered by the Spaniards. They were a race of peaceful people, but a race that jealously guarded the secrecy of their city. Into this realm biologist Alfred Bell ventured...