A FISHERMAN friend of mine once told me that there were only two sorts of books in his library -- those about fishing, and the others.

I, too, am a fisherman, and keep my fishing books on a most honorable shelf. Knowing that The River Way, David James Ducnan's first novel, contained many trout and salmon, and that its hero, Bus Orviston, was a flyfishing genius -- this I learned from the dust jacket -- I was prepared to enjoy a long winter's read. My qualms began on the second page. "Consider," says Gus, "when even a small quantity of water is inserted in a human posterior, a dramatic purgation results. Mightn't it follow that the constant proximity of vast quantities of the same fluid to a man's anterior could effect an analogous purgation?"

Forgive me, and forgive my pun, but the concept of a "cranial enema" does not move me. Jokes of this sort are commonplace in The River Why; Duncan does not have a light touch. Sometimes the book seems to have been written not with a pen but with a log. For instance: ""Simplify," said Henry Greenjeans Thoreau. "OK," said I: Life is a lot of green crap inexorably turning gray. The examined life ain't worth chub."

Though he is a fishing prodigy, Gus Orviston is also an adolescent, and he'd bend over backwards to avoid giving the appearance of being intellectual or even intelligent. This creates problems, for The River Why is an ambitious novel. Duncan aims at nothing less than wisdom, most of which must be conveyed through Gus. It would have been easier to make a camel pass through the eye of a needle.

Gus is the son of Henning Hale-Orviston (a name shortened to H2O), a famous fisherman-writer. H2O is a purist, the tweedy, pipe-smoking, Scotch-drinking upholder of the most gentlemanly angling traditions. Gus' Ma, Carolina Caper, is his opposite number. She smokes Camels, cusses, drinks cheap brandy, and, worst of all -- "O Heresy? Lower than Low Church, lower than parish, lower than poacher, predator, or polluter" -- she is a bait fisherman. She uses worms.

Does this sound a little schematic? These parents are not characters but cartoons; whatever resemblance they have to human beings is purely coincidental. H2O and Ma are philpsophical propositions, thesis and antithesis in "The Great Izaak Walton Controversy" which rages in the Orviston household. The result of this dialectic is Gus, or synthesis.

He fishes with flies and worms. Moreover, since he discovers that Walton's classic, The Compleat Angler, has less to do with fishing than with "that nebulous Personage whom men call God," he begins a "god-notebook" in which he records references to "R. Lord" and "Fathern Heaven." HIs spiritual exercises begin in earnest when he graduates from high school and lights out for a cabin on an Oregon coastal river which happens to spell out on the valley floor a single dread word: WHY. Gus decides to make an answer.

Enlightenment first comes to him during a conversation with his 10-year-old brother, Bill Bod. The child patiently explains all about "Garden Angels" who live in a Garden World ruled by a beautiful queen, and Gus thinks, "I'd like to get a look at this Queen. Somebody so beautiful she made you pop off like a million flashbulbs . . . wow! I was liking his cosmology more by the minute." Gus continues his cosmological inquiries under the tutelage of an improbable chap named Titus Gerard, and he achieves bliss when he meets the evermore improbable Eddy, a girl who is as fabulously beautiful as the queen of the Garden World and a sensational fisherman to boot. She strips naked to play big fish and her nose gives Gus the same feeling as "a baby cottontail rabbit's nose . . . the little fuzzy ones . . . You know, how when they scrunch them up to smell something; how cute it looks and everything . . ."

Yet Duncan, as I have said, has set out to be profound. This novel is awash with quotations, Tao parables, Indian legends, gleanings from Buddhism and Christianity. Gus' instinct is to make Rumi or Lao-tzu or Plotinus sound like just another one of the guys, someone to share beer and pizza with. Titus, older than Gus, speculates with greater force; the digressions from his notebooks are learned and original but, alas, too infrequent.

And though they are similarly infrequent, there are a number of memorable fishing scenes in The River Why. When Duncan stops laboring to be cosmological, he is able to write in a distinctive, confident voice about fish and rivers. At times the clean, fast water of the Northwest seems to run through these pages. Duncan has created one truly noble fish, a salmon, and one noble fisherman, an Indian named Thomas Bigeater.

Duncan's intention, I believe, was to write a novel like Zen and the Art of Motorcycle Maintenance, where the most mundane activities are linked to thinking of the highest order. In The River Why, unfortunately, the link is missing. Bigeater, a very minor character, is the only human thing in a novel which is otherwise a mystical-methaphysical fish story. Duncan can write about cutthroat and salmon, and he has something to say about R. Lord also referred to as The Whopper. What's absent is the human element, the only element that could fill the huge gap between the divine and the piscine.