SOURCE: Knight, Damon. “One Sane Man: Robert A. Heinlein.” In In Search of Wonder: Essays on Modern Science Fiction, pp. 76-89. Chicago: Advent Publishers, 1967.

In the following essay, Knight discusses the strengths and weaknesses of Robert A. Heinlein's science fiction stories and argues that he “is the nearest thing to a great writer the science fiction field has yet produced.”

Robert A. Heinlein has that attribute which the mathematician Hermann Weyl calls “the inexhaustibility of real things”: whatever you say about him, I find, turns out to be only partly true. If you point to his innate conservatism, as evidenced in the old-time finance of “The Man Who Sold the Moon,” you may feel smug for as much as a minute, until you remember the rampantly radical monetary system of Beyond This Horizon. One or two similar mistakes of mine are embedded in this [essay].

With due caution...