Robert A. Heinlein was one of the most revered science fiction writers in America during the twentieth century. He published his early, juvenile science fiction novels between 1947 and 1958, just as America was emerging from World War II and entering the space age. This comprehensive work explores Heinlein's juvenile novels, providing pertinent definitions and explanations to aid the reader. Of particular interest is the way in which Heinlein used science fiction to parallel the exploration of outer space with the settlement of the North American continent. Both Rocket Ship Galileo and Have Spacesuit--Will Travel are discussed. Appendices provide a precis of the plot of each book, and speculate on some of the names and terms for which no specific reference could be found.