By Mark Leyner

Harmony Books. 154 pp. Paperback, $7.95

The fiction of Mark Leyner -- if "fiction" is the word for it -- has acquired a small but rapidly growing following on college campuses. If your first thought on hearing this is to head for the exit, think again. On the evidence of this, his second book, Leyner is an original and immensely amusing writer as well as a provocative social critic; if they're reading him on the campuses, there may still be hope that the post-literate age is not yet upon us.

Leyner himself, to be sure, doesn't seem all that optimistic about the future of the written word. "Today, movies, videos and television can be so much more powerful than books," he said in a recent interview. "I think it's the responsibility of writers to try and compete with those mediums. I write for people who are used to playing with their remote controls."

What this means, when theory is put into practice, is a fiction that deals heavily in non sequitur and free association, that draws upon the information overload of contemporary culture to assault the reader with a barrage of seemingly unrelated factoids that somehow manage to acquire a certain off-the-wall coherence. Readers of Thomas Pynchon will find themselves in familiar territory here -- "A flying wing with no fuselage tows a face across the sky," Leyner writes in wry tribute to the master -- but imitation is scarcely Leyner's stock in trade.

The raw materials of his fiction are the stuff of everyday life: fast food, chemicals, Japanese audio-video gizmos, Korean automobiles, sex, violence, pop music, brand names, television, nuclear technology, racial and ethnic tension. The only way to explain him is to quote him:

"Cupping my ear to a bowl of Rice Krispies I hear German V-2 rockets falling on London Bridge. Unemployed laboratory mice laid off after cuts in federal research funding huddle in skid row alleyways guzzling miniature bottles of airline whiskey. ... Two elderly chimpanzees who, in the heyday of television documentaries about primate speech capacity, required sumptuous private dressing rooms with stars on the doors, now sit dejectedly in a Miami Beach laundromat using sign language to bemoan their dwindling pensions and persistent hemorrhoids."

No, it doesn't make much sense, but then there's no reason to believe that it's meant to. By putting an odd spin on the mundane, by twisting the ordinary into the improbable, Leyner at once ridicules and illuminates the preposterous juxtapositions of modern life -- which is to say that, at a certain level, Leyner makes a great deal of sense. The same goes for his more straightforward passages of social commentary:

"Soon psychopathology replaced ethnicity as the critical demographic determinant. There were no longer Italian neighborhoods, or Cuban neighborhoods, or Irish or Greek neighborhoods. There were Anorexic neighborhoods, and Narcissistic neighborhoods, and Manic and Compulsive neighborhoods. There was no longer a Columbus Day parade or a Puerto Rico Day parade; there was an Agoraphobics Day parade. Fifth Avenue lined with police barricades, traffic diverted. But, of course, the designated route was empty, utterly desolate, because the paraders, even the Grand Marshall himself -- agoraphobics each and every one -- had all stayed away, each locked within the 'safety' of his or her own home."

If by now you are wondering what this has to do with the narrator's cousin, the gastroenterologist, the answer is nothing at all -- nothing, at any rate, discernible to the naked eye. The book's title appears to be nothing more than a whim, inasmuch as the aforesaid cousin, "esteemed by his professional colleagues, affluent, and socially prominent, ... the shining scion of his immigrant family," is a barely detectable presence in Leyner's novel, if "novel" is indeed what it is.

In fact, what ties "My Cousin, My Gastroenterologist" together is neither character nor plot but the author's own wry, irreverent intelligence; like his narrator, Leyner "experiences each moment as if he were being alternately flayed alive and tickled to death," and it shows in every sentence of this mercilessly funny book. In the end, to be sure, Leyner admits that "I longed for the warm textures of flesh and blood -- the faint glimmers of sympathy and pleasure in a pair of eyes indicating the presence of a heart and nerves and synapses and not gallium arsenide chips and integrated circuits," which is all well and good; but it's the cold world outside that gets his juices flowing, and he depicts it with singular wit.