Matt and Laurel Gregg have been married for almost nine years. They have a 7-year-old son, Jonathan, and they have recently moved to Pittsburgh because Laurel, a family counselor, has found a job there. For Matt, who worked for a while as a police officer and then in a number of miscellaneous jobs, this move seems yet another downward step in a life that's been on the slide ever since an injury ended his hopes for a baseball career; for Laurel, though, the move is a step up, toward independence and self-fulfillment.

As if that weren't enough to put a marriage on the skids, Matt has taken a job, if you can call it that, as assistant to a private eye who investigates sleazy cases and works out of a rundown office. For Laurel, it is just about the last straw: "It was as if they were on a seesaw, Matt slowly going down while she was rising. The more success she had, the happier and more established she got, the worse things were for him. She couldn't fight a feeling that he was doing it on purpose, punishing her for being happy. She wanted to kick him, shout, 'Get off your a-- and do something! Take hold of your life!' "

Matt does something, all right, but it is not exactly what Laurel has in mind. In the course of tracking down witnesses to an accident, he becomes involved with Otto Droge, the operator of a pornography parlor, and Hugh Bollinger, a private-school teacher who is one of Droge's chief clients. Initially against his will, but with an appetite he cannot deny, Matt is drawn into the world of porn: "It was true that pornography got boring after a while . . . but for a few minutes it was astounding, a beautiful woman who did it all, enjoyed it all, who never said a man was doing it wrong, or doing something she didn't like, or doing something perverted. There were no clumsy men, such movies said, only frigid women. Such a message did not get boring right away."

For a while Matt is able to enjoy the fulfillment of this adolescent dream of available and compliant women with Angel, who offers him "the lure of the forbidden." Laurel, meantime, has begun an affair with one of her fellow counselors, who turns out to want a bit more from her than she is especially eager to give. Each finds out about the other, and a moment of crisis is reached:

"All through their marriage they had been pretending things to save one another; now there was no more pretending. She had seen him with the whore of his dreams, and he had seen her with the man she loved. Suddenly it all seemed rather silly . . . It seemed to him that finally they were two unattached people, who if they chose to stay together would be doing so not out of habit, or convention, but because they really wanted to."

By the time they have decided what it is they want, Matt and Laurel have been put through the paces. These include a murder, a dirty movie with ominous undertones, a potentially fatal encounter involving guns in uncertain hands, and an inordinate amount of confession by all parties. A thorough tour of the world of pornography is provided, and aspects of Pittsburgh are disclosed that the Chamber of Commerce doubtless would prefer kept secret.

It's all quite entertaining because David Guy is an able writer and a skillful satirist. His pen is sharp enough to wipe a character out in a few words: "She wore a light sleeveless summer dress that hung straight down on her chunky body. On her face was a purplish splotch of lipstick that looked as if someone had thrown it at her mouth from five feet away: an excellent shot, but not perfect. Her bare arms were muscular. She looked like a pulling guard in drag." Hardly a soul or a subject is spared Guy's withering prose; "The Man Who Loved Dirty Books" may be cruel, but it certainly is fun.

Unfortunately, though, Guy seems to want to have it both ways. Not merely has he written a satire on pornography and the illusions upon which it feeds, but he has himself written a dirty book. There is a degree of explicit sexual description in this novel that just about every post-pubescent reader is likely to find excessive in the extreme; a five-page encounter between Matt and Laurel in a cheap boarding house is perhaps the most offensively detailed, but there are many others. If Guy is trying to say that there is a crucial difference between the "world of sexual acts" that the pornographers inhabit and the world of sexual love that ordinary people aspire to, he has chosen a curious way to describe it; in "The Man Who Loved Dirty Books," the two worlds sound exactly alike.