Campbell praised its logic as magnificent, especially “the mass of small details that made it real,” which he identified decades later as the author’s primary contribution to the genre: Cultural patterns change; one of the things Heinlein “invented” was the use of that fact. . . . Like the highly skilled acrobat, he makes his feats seem the natural, easy, simple way—but after you’ve finished and enjoyed one of his stories . . . notice how much of the cultural-technological pattern he has put over, without impressing you, at any point, with a two-minute lecture on the pattern of the time.
