THERE are mysteries aplenty in The Mysteries of Pittsburgh, but they are mysteries of character and not intrigue.

The Mysteries of Pittsburgh

By Michael Chabon

William Morrow and Co., 297 pp. 1988

There is the mystery of the hero's sexuality. Is Art Bechstein, who is graduating from college as the novel opens, heterosexual or homosexual? Both or neither

Bechstein's girlfriend, Phlox, works in a library. Bechstein's boyfriend, Arthur, works in the same library. At one point, Bechstein confronts both of them, and offers: "I love you, Phlox. And I love you, Arthur." For as long as he is able--and Phlox and Arthur make it increasingly difficult--Bechstein straddles the sexual fence.

There is the mystery of Bechstein's spiritual state. Which life will become his model, that of his father--a lord of the underworld--or of Cleveland--an insouciant motorcylist? The two sit on opposite ends of Bechstein's spirtual seesaw. His father, head of a numbers racket and prostitution ring, is willing to forget the past in order to enjoy the present, and the world be damned. Cleveland, who would like to get involved in the same underworld life, hangs out at the Cloud Factory--the name he assigns to one of Pittsburgh's omnipresent smokestacks--his thoughts often floating far above it.

There is the mystery of Bechstein's early years. Bechstein's mother died under peculiar circumstances when he was young. Throughout the novel, he grows ever more curious about how and why his mother died.

MICHAEL Chabon, whose short stories have appeared in The New Yorker, is following in the footsteps of Jack Kerouac and J.D. Salinger with this novel. Like Kerouac, Chabon seeks to explore the outskirts of human discontent and disillusionment. Like Salinger in The Catcher in the Rye, he writes about a certain time--in Bechstein's case, a summer--charged with uncertainty and doubt.

Although this is his first novel, Chabon manages to convey his hero's journey in prose void of fatuousness or sentimentality. It is not fair to compare him, as his publisher has, to F. Scott Fitzgerald. Chabon's words do not have a jazzy tone; they sing in a disjointed melody, a music chopped into bits of drama and contemplation. Besides, being the next F. Scott Fitzgerald today often means finding your book in the bargain bins tomorrow.

Chabon is one in a long line of young novelists to examine the strange bric-a-brac of our day. Unlike Jay McInerney--whose debut novel, Bright Lights, Big City, was a dirge devoid of rebirth, and set in the heart of the New World jungle, New York City--Chabon retains a Midwestern sensibility and even-mindedness. Chabon's prose can be as funny as McInerney's, but its message is more cheerful.

Pittsburgh, the Steel Town, stands in stubborn contrast to dissolute New York. New York can swallow you whole; Pittsburgh merely chews you a little before spitting you back on the plate. In Pittsburgh, there is still a dream of a greater life--thus the recurring image of the Cloud Factory in Chabon's novel. In New York, there are the lights, which blind you, and the bigness in which you lose yourself.

Like the young John Updike, Chabon treats sexuality as a problem that confuses and subsumes other issues. But in Chabon's novel the problems of homosexuality--to say nothing of sexuality--are placed in the larger context of the struggle for an identity of which sexual identity is only a part.

For Bechstein, the summer is like a canvas on which he can apply the colors of his passions and peculiarities. First, he meets Arthur. Then Arthur introduces him to Phlox and Cleveland. Soon, he comes in contact with a world he had barely scraped the surface of in his early years: his father's world. Pittsburgh--smoke-filled and grim--serves as an an appropriate counterpoint to Bechstein's colorful journey.

Bechstein's adventure is like that of T.S. Eliot's in "Four Quartets." At the end of his destination, Bechstein arrives at the same place he had been, only to find it different than he had remembered it. In retrospect, he appreciates the journey, which grows to heroic proportions in his memory.

"When I remember that dizzy summer, that dull, stupid, lovely, dire summer, it seems that in those days I ate my lunches, smelled another's skin, noticed a shade of yellow, even simply sat, with greater lust and hopefulness--and that I lusted with greater faith, hoped with greater abandon. The people I loved were celebrities, surrounded by rumor and fanfare; the places I sat with them, movie lots and monuments."

The novelist's themes are heavy. But the novelist's touch is light. Throughout his adventures, which bring him to the brink of tragedy on several occasions, Bechstein remains amused and amusing.

Early in the novel, he visits Arthur, who is house-sitting for the Bell-weathers, a snobbish couple. Cleveland arrives and discovers that the family's precious pooch is in heat. Cleveland invites a neighbor's three dogs over for an orgy.

When the Bellweathers return, chaos erupts:

" 'What have you done to our dog?' " said Mrs. Bellwether--to Cleveland....

"Arthur started to say 'Nothing,' but Cleveland interrupted him.

" 'We bashed her head with a ball-peen hammer,' he said."

Bechstein's summer journey is interrupted every so often by the appearance of his father. As the summer wears on, Bechstein's visits with his father become more painful; he begins to see the man behind the mob. For Bechstein, his father is both a ghost, of a life he left behind, and a portent, of future that may await him.

Bechstein finds the past in the future. And the past must be discovered, as painful as that discovery is, lest it remain a haunting mystery.