New York, Scribners, 1950. First Edition. First Impression. One of only five Retro Hugo award winners, the other four being Slan, The Sword in the Stone, Fahrenheit 451 and Mule, a part of Asimov's Foundation Trilogy. A novel without doubt amongst good company. One of Heinlein's early juvenile novels. Heinlein's fourth children's novel. Serialised in Boy's Life in a shorter version in the same year. Very good condition. Some chipping to the corners of the jacket, front fold with an inch-long tear, head and tail of spine moderately chipped, a number of short tears. Owner's inscription in pencil. Spine tips a touch bumped. Acceptable copy. Illustrations by Clifford Geary [5915, Hyraxia Books].