Smut investigates sex in a way that differes from nearly all previous books on the subject. Drawing on a wide variety of literary forms, including the work of novelists, poets, and even comedians–resources ranging from the most sublime theologians to the most profane pornographers–Murray S. Davis goes beyond those who regard sex merely as a biological instinct or animal behavior. He recaptures sex for the social sciences by reemphasizing the aspects of it that are unique to human beings in all their rich perplexity.

In part one, Davis employs a phenomenlogical approach to examine the differrence between sexual arousal and ordinary experience: sexual arousal, he argues, alters a person's experience of the world, resulting in an "erotic reality" that contratsts strikingly to our everyday reality; different perceptions of time, space, human bodies, and other social types occur in  each realm. Davis describes in detail the movement from everyday into erotic reality from the first subtle castings-off to the shocking post-orgasmic return.

In part two the author employs a structuralist approach to determine why some people find this alternation between realities "dirty." He begins with a meditation on the similarity between sex and dirt and then asks, "How must somone view the world for him to find sex dirty?" Normal sex can be disliked, Davis concludes, only if it violates a certain conception of the individual; perverted sex can be despised only if it further violates certain conceptions of social relations and social organization. Davis ends part two with a "periodic table of perversions" that systematically summarizes the fundamental social elements out of which those who find sex dirty construct their world.

Finally, in part three Davis considers other conceptual grids affected by the alternation between everyday and erotic realities: the "pornographic," which concieves of the individual, social relations, and social organizations as deserving to disrupted by sex; and the "naturalistic," which concieves of them in a way that cannot be disrupted by sex. Throughout history these ideologies have contested for control over Western society, and, in his conlusion, Davis ofers a prognosis for the future of sex based on these historical ideological cycles.