The Heinlein juveniles are the science fiction novels written by Robert A. Heinlein for Scribner's young-adult line. Each features "a young male protagonist entering the adult world of conflict, decisions, and responsibilities." Together they tell a loosely-connected story of space exploration. Scribner's published the first twelve between 1947 and 1958, but rejected the thirteenth, Starship Troopers. That one was instead published by Putnam. A fourteenth novel, Podkayne of Mars, is sometimes listed as a "Heinlein juvenile", although Heinlein himself did not consider it to be one.