|Abstract||One analysis of humor that provides a useful framework for the consideration of humor in the science fiction short story is Max Eastman's Enjoyment of Laughter, in which he divides humor into two broad categories, the ludicrous and the witty. This study examines these two types of humor in stories on three central themes of science fiction: society, gadgetry, and the alien. Most stories on future societies are dystopian and rarely funny, though some, especially those dealing with education, business, and the military, can be. The humor in these is usually satiric, sounding a warning, and so approaches the black humor of modern mainstream fiction more closely than that found in other areas of science fiction. Stories of gadgetry fall into three categories: stories of time and dimension, which usually employ a machine to manipulate time or space; the gadget story proper, and the robot story. The time or dimension story usually is grounded in incongruity arising from the dislocation of time or space. The gadget story generally has the most superficial, naive humor in science fiction; the writer invents a humorous gadget or one with humorous consequences just for the fun of it. The robot story, especially those in which the robot takes on human qualities, has the richest possibilities of the three for humor, deriving from the incongruities of a machine becoming a person and acting in human ways. The common element in all these varieties of gadgetry is that, in some way, a machine gets out of control. The most sophisticated humor is found in stories about aliens, the humor arising from the interaction of human and alien cultures and personalities. For humor the aliens must have enough human qualities to be funny in the same way humans are, but directing the laughter at aliens avoids the stigma of cruelty such laughter would have if directed toward humans. There is relatively little humor in science fiction, largely because writers and critics seldom view science fiction as primarily an entertainment genre. This attitude has prevented science fiction from realizing its full potential for humor.