Chaim Potok and his wife, Adena, chanced upon the pear-shaped butternut wood instrument during the summer of 1983, while browsing in a Vermont country store. The proprietor explained that it was a door harp, commonly found in the entryways of local houses. Captivated by the sounds the four maplewood balls made as they struck the piano strings, the Potoks bought it and hung it in their kitchen.

Two years later the harp has emerged as the prominent and resonant symbol in Potok's sixth and latest novel, Davita's Harp (Knopf, $16.95). This time the bearded, best-selling chronicler of life among the Hasidim (The Chosen, The Promise, My Name Is Asher Lev) turns to the political turbulence of New York in the 1930s, liana Davita Chandal is the daughter of Michael Chandal, a WASP newspaperman, and his Polish-Jewish wife, Channah. Both are fervent communists and atheists. A baffled observer of the meetings her parents hold at home, Davita, as she grows older, searches out security in the rituals of Judaism. In spite of her parents' disapproval, Davita becomes interested in religion and later enrolls in the local yeshiva. There she wins top marks, entitling her to the Akiva Award, given to the best student. Instead, the prize is given to a boy. "What would all the other yeshivas think of us?" a Hebrew teacher asks the devastated youngster. "What would the world think about our boys?"

"That actually happened to my wife when she was a young girl in Brooklyn," Potok, 56, says, seated in the library of the Tudor house outside Philadelphia, where he lives with his wife and three children. "I've known about it since we were married. Those things sit like a seed in the core of your being. Finally I decided it was time to haul it out and take another look at it. The harp got mixed in along the way and became the central metaphor."

Potok's surroundings mirror the many sides of a writer who has by turns dazzled, disappointed and baffled critics. In the bookcase are the religious texts of Potok the ordained rabbi. Alongside are the numerous bound novels of Potok the best-selling author. There are also copies of Wanderings: Chaim Potok's History of the Jews, on which he spent four years of painstaking research in Jerusalem. Above the bookcases are some Munch-like Expressionist paintings. Potok is also an accomplished painter.

In fact, though Potok's novels are set in the narrow world of Orthodox Jews, more than half of his readers are non-Jews. "I write about Jews because it's what I know best," he says. "The human problems that affect them affect any particular group—Lutherans, Seventh-day Adventists, Mormons. My characters are comfortable inside the framework of their tradition but they keep bumping into and up against ideas from the civilization around them. Davita follows the pattern. She doesn't break away in terms of deeds. She breaks away in her mind."

Much the same could be said of Potok, whose father, Benjamin, emigrated to the U.S. from Poland in 1921. As a boy in the East Bronx, Chaim wanted to be a painter. His father, a jeweler, wanted him to be a teacher at a Talmud academy. At 16, after reading Evelyn Waugh's Brideshead Revisited, he turned to writing. "I'll never forget thinking what power there was in words," he says. Though his father considered both painting and writing to be worthless, gentile enterprises, writing seemed more acceptable. "At 17 I sent a story to the Atlantic Monthly, and an editor wrote back an encouraging letter," he recalls. "My father was furious, but it carried me a long way." Majoring in English literature, he graduated from Yeshiva University in 1950 summa cum laude and promptly enrolled in the Jewish Theological Seminary, where he was ordained as a Conservative rabbi in 1954. "I never wanted to be a pulpit rabbi," he says. "But I went to the seminary in order to study what it was I wanted to write about."

Suddenly Potok was ordered to Korea as an Army chaplain, like his character Gershon Loran in The Book of Lights. The experience transformed him. "I saw suffering the likes of which I never envisaged in my wildest nightmares. And I saw exquisite, forbidden, pagan beauty. And a culture perfectly at ease without Jews or Judaism."

Potok returned home and enrolled in a doctoral program in philosophy at the University of Pennsylvania. Adena, now 52, supported the family as a psychiatric social worker. "We lived dollar to dollar in those days," he says. "We didn't have a penny in the bank. One day I got an offer of three separate pulpits. Each one paid $20,000, which in 1963 was a lot of money. I was working on The Chosen, and I remember telling my wife, 'I've been offered this but I don't want to do it. I want to write.' She said, 'Go ahead.' " When the book was published to critical success four years later, financial pressure eased. Potok worked as editor of the Jewish Publication Society in Philadelphia and began to turn out a novel about every three years.

Ironically, for a novelist in the mainstream of Jewish writing, Potok has proved most provocative to Jews themselves. Shortly after its publication, The Chosen was banned from Orthodox yeshivas. Potok himself was declared persona non grata at several synagogues. "My books upset the Orthodox for a couple of reasons," he explains. "First, the characters end up just a little more secular than they started out. Second, the Orthodox just don't like being written about. The important thing is the study of sacred texts. Writing is a horrible waste of precious Jewish time." Potok smiles knowingly. "Still, they read me."