This compilation of three of Heinlein's "juveniles" for Scribners are three of his best. To this group I would also add "Have Spacesuit, Will Travel", "The Star Beast" and "Between Planets". Can you think of other SF written in the 50s that are as readable as these? I can't. And they are great, collected together.These are timeless stories that are worth reading and rereading over the years, and show why Robert Anson Heinlein is still a master at engaging, informative, and just fun SF.