Ever since a wise-cracking, motorscooter-riding kangaroo named Joey Castle pistol-whipped Conrad Metcalf in the parking lot of the Bayview Adult Motor Inn in Gun with Occasional Music, Jonathan Lethem has had the world of mainstream literary fiction looking nervously over its shoulder. When that novel, Lethem's first, was published without fanfare by Harcourt Brace in 1994, most reviews labeled it a mystery novel, "a very strange one," the 34-year-old author recalls. But in fact, Lethem never saw himself as a mystery writer at all. Even as he was writing Gun he had another, wholly different project on the back burner: Amnesia Moon, a post-apocalyptic American desert road novel. Then came an eclectic science fiction story collection, The Wall of the Sky, the Wall of the Eye, and last year's As She Climbed Across the Table, a love story and academic satire with a Lethem twist: it turns out that one of the competitors for particle physicist Alice Coomb's affections is a highly charismatic black hole known as Lack.

It is difficult to see the author of these outrageous fictional scenarios in the restrained, rather ascetic-looking young intellectual who discusses them so earnestly and intently with PW. With his stylishly spartan wire-rimmed glasses, dark V-neck sweater and close-cropped hair, Lethem has nothing of the mad genius about him. It's as if he had harnessed every bit of inner ferment and rebellion -- against social and literary expectation -- and turned them toward the writing of his books.

As case in point, take his latest novel, Girl in Landscape (Doubleday), a beautiful but grim work that exists somewhere in the previously uncharted interstices between science fiction, western and coming-of-age novels. Most of the characters who run amok through its pages are ordinary children -- which is to say, rebellious, sexually curious and violent -- who experiment with all sorts of forbidden fruits, including a visionary out-of-body state that is reached, perversely enough, by not taking drugs. A maverick John Wayne-type character looms in the background for most of the tale, his figure starkly silhouetted against the backdrop of an alien sky, but he meets his match in the precocious adolescent protagonist, Pella. "Where did I find the confidence to write from the point of view of a 13-year-old girl?" Lethem asks. "She comes out of impulses and emotions in me. The fact of her being a girl is secondary." Lethem's confessed external sources for the story were Carson McCullers and Shirley Jackson, for that "tomboy-coming-of-age-sexual awakening vibe," and his obsession with the John Ford film The Searchers, in which the John Wayne character tries to rescue a young girl who has been abducted by Indians. "It's an obsessive quest, and he's an anti-heroic, racist, angry figure. I wanted to explore what it was like to have your sexual coming-of-age watched over by this bullying man," Lethem says. Although it takes place on another planet, Lethem argues that Girl is less about science fiction than any of this other novels. "I'm very proud of Girl in Landscape," he says. "I know it's a weird one, but I think it's the most novelistic of any book I've written."

For an author whose first book came out in 1994, the phrase "any book I've written" sounds almost glib, but when asked about his prolific output -- five books in as many years -- Lethem demurs. "It's a real sleight-of-hand that's about to be exposed." It turns out he hasn't really been writing a book a year. It's just that he ended up finishing 10 years worth of work in a five-year period, and now he's more or less caught up with himself. Of course, that still adds up to a book every other year -- a pretty good clip by most standards.

Lethem grew up in Brooklyn, N.Y., the son of an "unfamous painter" dedicated to his art but always forced to work another job. Growing up, Lethem looked forward to a similar career. He studied painting at the High School of Music and Art, in Harlem, and spent the long subway rides to and from Manhattan engrossed in novels that were not on his high school syllabus, whether because they were a little too weird, a little too low-brow or a little too avant-garde. The list of his early influences is eclectic-including Philip K. Dick, Charles Willeford, Jim Thompson, Thomas Pynchon and Kurt Vonnegut -- and it provides a key to Lethem's sensibility, his scorn for what he calls "the obsolescence of bankrupt categories," his exuberant, intellectually sophisticated emulsion of high and low. From the age of 15 until the year Gun came out, Lethem worked in a series of small, out-of-the-way secondhand bookshops in New York City and California. In the 1980s, he was reading books that had come out 10 years before, "because that's what the used bookstores are loaded with" -- a habit he still maintains, although he cites Jeffrey Eugenides, David Bowman and Ian McEwan as contemporaries whose work he follows with particular interest. Although Lethem attended Bennington College (for just three semesters) during the period when Donna Tartt and Bret Easton Ellis were there, Lethem was a studio art major, not part of the writing crowd, and kept his own attempts at fiction under the table. He finished a first novel, which was never published, about the time he would have graduated, but says he knew as soon as it was finished that it wasn't any good. "It was just the X number of bad pages I had to write," he says. He started writing stories after that and moved to Berkeley, where again he eked out a meager existence on used-bookshop wages and wrote whenever he wasn't at work. Although he was never affiliated with the university, Lethem was briefly married to a graduate student there, Shelley Jackson, and his experiences with her were part of the inspiration for As She Climbed Across the Table. The book is dedicated to her, though they were divorced by the time he finished it. "If you asked me then, I would have said I'd be working at bookstores until I was 45," he says. "You have to understand -- all my her s were dark horses. They all had embattled careers because of genre prejudice, something I've had the good fortune to be spared. It's like I'm standing on their shoulders. I sort of feel Philip K. Dick died for my sins."

Indeed, recognition of Lethem's writing did come relatively quickly. The hard part was finding an agent, which took about a year and entailed some frustrating rejections. Lethem says he would have taken pretty much anyone who would have him, when he finally stumbled into a happy association with Richard Parks (who remains his agent today). A year and a half later Parks placed Gun with Michael Kandel at Harcourt Brace. Then, in March of 1994, just when Gun was being released, Kandel was fired. The book might have been orphaned had it not been so cheap to publish. The advance was only $6000, and there was no publicity campaign to cancel. Lethem's greatest concern was the loss of a sympathetic line-editor, especially since they had just signed a contract for Amnesia Moon.

Gun, with a Bullet

That was when things suddenly began to turn around for Lethem. A reviewer at Newsweek noticed Gun in the vast pile of unheralded review copies. Characterizing it as an "audaciously assured first novel," Newsweek's write-up catapulted the previously obscure book to the public's attention. "There are certain nodes of centralized cultural power," Lethem muses. "It's scary, but it's nice to have one of them working on your side when it happens."

The big change occurred when Alan Pakula optioned the movie rights, enabling Lethem to quit the bookstore and write full time. Since he never expected his subsequent books to do so well, Lethem tried to stretch the money from Gun as far as possible, living what he calls a "bohemian garret existence." Harcourt Brace eventually rehired Kandel, who oversaw the publication of Amnesia Moon and acquired The Wall of the Sky. Paperback rights for the first three books sold to St. Martin's, and foreign sales have been strong. Lethem's next three books, As She Climbed Across the Table, Girl in Landscape and the novel, as yet untitled, that he's working on now, were all bought by Bill Thomas at Doubleday. David Lynch and a partner recently optioned Amnesia Moon. Lethem seems particularly pleased as he pulls from his shelf the new Vintage Contemporaries edition of As She Climbed Across the Table. Vintage has also bought paperback rights to Girl in Landscape. "It's really flattering to be in Vintage Contemporaries because I read that line with so much enthusiasm in my 20s. I discovered Richard Ford that way, Frederick Exley, so many writers," Lethem observes.

As a result of this commercial success Lethem is now able to write full time, but the most important thing, he says, is that his books are widely read. "I'm completely in print, which is amazing. I don't know how long it will last, but it's exciting to me to know that my work is out there in the cultural fray." He g s to his desk for a newspaper clip showing Holly Hunter and several other actors after a staged reading of a story from The Wall of the Sky, the Wall of the Eye. "It's thrilling because that reading had nothing to do with New York literary hype. It came from someone's excitement at reading my work."

After 10 years in California, Lethem returned to his hometown of Brooklyn a year and a half ago because, he says, he wanted to live in the city that will be the setting for his next two novels (which are not otherwise linked). He lives and writes in a tar-papered walk-up in the largely Polish neighborhood of Greenpoint, far from the nearest Manhattan-bound subway station. The area of the apartment dedicated to living space is simple, spare, yet comfortable, bed tucked into a hallway alcove, tiny living room furnished with a 1950s armchair and a sleek vinyl-covered couch. One wall is lined from floor to ceiling with narrow-gauge bookshelves perfectly suited to Lethem's collections of pulp paperbacks. The office is by far the largest room in the apartment -- one that a less single-minded person might have used as the bedroom or living room. Lethem says he gets up in the morning and g s straight to work, often not leaving the house until lunchtime, when he ambles to a local Thai restaurant for a bowl of noodle soup as a way of breaking up the day. There are days when his only outing is a quick visit to the newsstand for a paper.

Brooklyn makes a cameo appearance in Girl in Landscape, as a ravaged, barely inhabitable eco-nightmare of a city, but the scene quickly shifts to the Planet of the Archbuilders, a frontier reminiscent of the wild west. "I was putting my t s in the water for coming back home to Brooklyn in Girl in Landscape," Lethem says. He characterizes the Brooklyn book he's working on now as "a sort of a madcap crime novel -- not a mystery because there are no murders, clues, solutions, but the characters are rascals." An "Oliver Sacks type" neurological dysfunction is prominently featured in the story, and the voice shares some of the zaniness of Gun and As She Climbed Across the Table. Whimsy is important in all Lethem's books, even the comparatively dark Girl in Landscape, in which the language-obsessed alien characters, enamored of what they consider the poetic possibilities of English, take names like Lonely Dumptruck, Specious Axiomatic and Somber Fluid.

This persistent, playful humor, which tends to support serious thematic concerns, is one of the ways Lethem manages to pull off such improbable narrative stunts. "There are a lot of things in my books that come from a need to keep myself amused during the long, lonely writing day. I try to avoid taking myself too seriously. That would be toxic."