SEEK
Reports from The Edges of America and Beyond
By Denis Johnson.
238 pp. New York:
HarperCollins Publishers. $24.

THERE is a special pleasure in seeing a writer of Denis Johnson's caliber try something that is not his specialty. ''Seek,'' a collection of his forays into nonfiction, reads like an extended experiment -- short and long pieces of journalism and memoir whose subjects range from wars in Africa to cards at his local bar, where the tense is usually past but occasionally present and sometimes both, and where the voice seems continually under construction. Johnson, who uses the fictional first person to impressive effect in stories like those in ''Jesus' Son,'' seems unable to bear the ''I'' here, and so, awkwardly, refers to himself as ''the man from Idaho,'' as ''Moon One,'' even as one of ''a couple of American journalists.'' But he is such an adept that even his failures intrigue; and when he succeeds, the results can be spectacular.

The strongest writing here is in two pieces about the war in Liberia that bracket the collection. ''The Civil War in Hell,'' first published in Esquire, recounts a visit to the capital in 1990. Monrovia lies in ruins, its remaining inhabitants harrowed by cholera and warring, starving soldiers; the only creatures prospering are the dogs, ''because they feed on human corpses. The people are starving, but the dogs have put on weight.''

The conjuring of nightmare is a staple of Johnson's fiction, and it's what he does here, too: the situation in Monrovia would seem to spare him the need to invent. Driven through town to the former compound of a mining company, ''the journalists'' find the military leader Prince Johnson in the middle of his morning concert, ''gripping an acoustic guitar and singing 'Rivers of Babylon,' a Creole-reggae version of Psalm 137'' to his troops. In an interview, they ask him about the death of Samuel K. Doe, the president, a month before. Prince Johnson insists that Doe died of wounds received during his capture, but then reveals matter-of-factly, '' 'I cut off his ears and made him eat them.'

''The journalists believe they haven't heard him right. Made him eat what?

'' 'I have a videotape of this interrogation,' Johnson says suddenly. 'Would you like to see it?' ''

The description that follows, as the video is screened on a patio, is astonishing. ''On the screen, Samuel K. Doe, president of Liberia, sits on a floor in his underpants,'' it begins, ''his shirt open, his hands tied behind his back, his bleeding legs stretched out before him, bound tightly at the ankles.'' To this dystopia of video and reggae alongside timeless barbarism, Johnson is the perfect witness.

Next comes something quite different. ''Hippies,'' published last summer in The Paris Review, is a chatty memoir of Johnson's visit with two friends to a gathering of the Rainbow Family in a national forest in Oregon. ''Tens of thousands of hippies in the woods, seven days of Peace and Love.'' Johnson and one of the friends had ''taken our first acid trip together'' years before, and one suspects that drugs will figure prominently in the pages ahead, but what makes the journey interesting and unpredictable is the writer's admission in the second paragraph -- apropos of the hippie ethos -- I who have had so much of peace and so much of love, I have never really believed in either one.'' It is the first of several artful yet startlingly blunt statements Johnson will make about himself in these pages, each of them serving to bring him closer to the reader while, at the same time, establishing his distance from the subject and making clear that he is, in many ways, the anti-hippie. ''I've brought a couple hundred dollars in my pocket because . . . I don't care what they say, I've never seen anybody trade dope for anything except sex or cash.''

Johnson and Joey score some mushrooms (''I said I'd split it, but I only gave him about a quarter. Less than a quarter. Yeah. I never quite became a hippie. And I'll never stop being a junkie''), and the piece concludes with the resulting drug trip. For some reason, descriptions of such trips seldom work in nonfiction and Johnson's, unfortunately, is no exception. It left me wishing I were immersed instead in the sublimated hallucinations of his novel ''The Name of the World.''

Between ''Hippies'' and ''The Small Boys' Unit,'' the concluding piece on Liberia, are eight that range in quality from O.K. to pretty bad. The subjects of several are true believers: an Arizona cult; the flight of the accused abortion clinic bomber Eric Rudolph; a Christian revivalist motorcycle meet; Kabul, Afghanistan, under the Taliban. In each story are glimpses of the talent that explains why Johnson's fiction is so widely admired, as well as many pages where I found myself thinking, ''This would never have gotten published if he weren't Denis Johnson.''

But dwelling on these shortcomings will only delay our arrival at the book's superb closing piece, ''The Small Boys' Unit.'' In the winter of 1992, Johnson was sent back to Liberia, this time by The New Yorker, with the mission of profiling another Liberian rebel, Charles Taylor, the ''self-described president of Liberia.'' Through Taylor's representatives, the magazine had arranged for Johnson to enter Liberia through Ivory Coast and be escorted overland to his rural headquarters.

But the trip is a disaster from the moment nobody meets Johnson at the airport. This is due partly to the elusiveness of Taylor, partly to the frustrations of Africa and partly to the impatience and poor judgment of Johnson himself, about which he is characteristically candid. Against the advice of his local guide, for example, he tries to bribe a police commissioner in Ivory Coast in the hope of getting quick permission to cross the border; the man is offended and tells him he must first go to the capital. But then, across the hall, Johnson's passport is mistakenly stamped ''Liberia''; he rushes off to the border before the authorities can realize their mistake. This error will result in his arrest when, weeks later, he returns to Ivory Coast.

In Liberia he is kept waiting, waiting, waiting -- and Johnson is not a patient man. As he misses a ride to Taylor's compound and learns that a broken radio will further delay him, he encapsulates his reaction in a short, explosive paragraph that begins, ''My parents raised me to love all the earth's peoples'' and ends with an intimate, ugly fantasy about screaming a racial epithet repeatedly until ''one of these young men emptied a whole clip into me.'' It's the kind of sentiment you would never get from a seasoned correspondent, and if it doesn't confirm your worst fears about white people from Idaho, it may make you admire Johnson's candor.

Finally, Johnson nears his quarry. The small boys of the title are Taylor's personal guard -- war orphans whom Taylor has personally cared for and who are said to be fanatically loyal. In their custody is a man they claim is a spy and have been torturing. Johnson decides the man is innocent and, in what he concedes was ''a bizarre gesture,'' places his New Yorker ID around the prisoner's neck and calls out both of their names, and the names of the magazine and the United States, claiming that ''the magic from these names would stand around him against his misfortunes.'' His escorts succeed in diverting him to the long-awaited interview with Taylor. It is brief and unenlightening, and at the end of it, Johnson writes: ''My assignment in Liberia was over. As far as I could see at the time and as far as I can see now, I accomplished nothing.''

But it's worse than that: back in police custody in Ivory Coast, he knows he's in trouble but doesn't seem to realize that those who helped him sneak across the border are too; witlessly he gives up their names, and they are arrested. ''A dozen half-naked Liberian men now stood in a line with their hands bound behind them. . . . They all stared at me with sorrow and rage as I passed by.'' Recanting undoes only some of the damage. ''I'd come to this place and I was not whole enough or real enough to accept its terms,'' he confesses. Johnson's dark and violent fiction has prepared us for some of what we find in ''Seek,'' but ultimately it's his confrontation with the truth -- particularly about himself -- that gives the book its flashes of brilliance.