Regularly every year Robert A. Heinlein produces the best juvenile science fiction novel—and in so doing creates a work more maturely satisfying than 90 per cent of "adult" science fiction. "The Star Beast" … equals any of his previous books in lively adventure, and perhaps surpasses them in charm and in fullness of characterization (human and alien). The story of a boy and his pet always attracts readers; here the pet is a titanic but lovable monster from outer space, and the politics and even the future existence of Earth comes to hinge upon its identity and origin. The future civilization is developed with all the meticulous ingenuity one expects of Heinlein, but the emphasis is on individuals.

H. H. Holmes, in his review of "The Star Beast," in New York Herald Tribune Book Review (© I.H.T. Corporation), November 28, 1954, p. 16.