Mark Helprin likes to scale heights like the rock wall above New York's Hudson River at right, although when he climbed the 14,690-foot Matterhorn in the Swiss Alps last July, the 36-year-old writer got only three-quarters of the way up. A few months later, when his sprawling romantic fable, Winter's Tale, inched onto the best-seller list, Helprin was ecstatic. From the start of his assault, the writer had weathered several very heavy reviews, including charges that his 673-page tome was "without substance" and "sophomoric at heart." But Helprin was well equipped to survive such onslaughts: He had sold Winter's Tale to Harcourt Brace Jovan-ovich at auction for $250,000, and last month the paperback rights were sold to Pocket Books for $350,000, half of which is the author's share. "I'm sort of murdered for selling books," Helprin complains of the bad reviews. "The idea is, if you make money your work can't be literary."

The author of three other books of fiction, Helprin actually is a gifted maverick who knows how to play the game. He is also an intense man with a fertile imagination who becomes reclusive when he's working. Winter's Tale, which took him more than three years to complete, is set in New York and runs all the way from the turn of this century to the third millennium. Populating the book are a supernatural white horse, fanciful knaves called woola boys and romanticized damsels. In the ultimate urban renewal near the book's end, New York is destroyed and a new city, "infinitely complex, holy and alive," arises from its ashes.

Manhattan is Helprin's birthplace. The only child of former Broadway leading lady Eleanor Lynn and film executive Morris Helprin, Mark was trundled off to suburban Ossining, N.Y. at 6. His mother had a brief film career, but it was his father who regaled him with stories of Hollywood: As a boy in California, he had been one of the local kids on whom Charlie Chaplin had tested his films. Mark likes to embellish his past by claiming he was raised in a mansion in Ossining instead of in the smaller carriage house where he actually dwelt. "Mark was very much a loner," his father recalls. "He practically grew up in the woods." His main companion, Mark says, was a boxer dog who looked "sort of like Faye Dunaway."

While an English major at Harvard, he bombarded magazines with "about 50" stories, finally selling one to The New Yorker for $1,000 at age 21. "I think Mark always had a desire to be famous," confides a friend. Graduating in 1969, Helprin, whose ancestry is Jewish, spent a year traveling in Israel before returning to Harvard for a master's in Middle Eastern studies. About that time he married Judith di Leo, a Wellesley art student. A year later he joined the Israeli infantry—an experience he used in his first novel, Refiner's Fire. "I did everything for 10 minutes," he says.

His marriage lasted longer, until 1975. "We became different people" is his simple postmortem. Of his second wife, the former Lisa Kennedy, a tax lawyer who became the prototype for several of his heroines, Helprin says, "She's a pillar of many things, not just strength, but virtue and beauty." The marriage has worn well, in part, Lisa says, because "Mark has a sense of humor," and, she adds, "Sometimes when he goes away on a trip he'll even put some unusual object like a potato under my pillow to remind me of him."

Helprin is now working on another novel, but he also talks vaguely of going into politics. Isn't that more fancifulness? "Writing is still my main career, but I would love, for instance, to serve in the New York State Assembly," he says, and then, looking down on the contemporary literary scene, he insists, "I don't aspire at present to be king of the hill in American literature."