Layla, the heroine in Susanne Pari's first novel, "The Fortune Catcher," is a half-Jewish, half-Muslim Iranian woman with an American education.

Her cousin, Mariam, tells her, "No one can be two things — be East and West, be Moslem and Jewish, be Iranian and American — at the same time. We all have to choose."

Layla refuses to buy that argument.

Pari, an Iranian American who grew up with both Muslim and Jewish traditions, is living proof that one can be all these things.

In "The Fortune Catcher," Layla's Jewish grandmother rejects her daughter for marrying a Muslim. Layla's Muslim grandmother-in-law, Maman Bozorg, despises Layla, in part for being a Jew. When she hears that Layla is pregnant, she is horrified.

"A child! Surely not a child! From the seed of that daughter of a Jew! It cannot be," Maman Bozorg says.

Pari, who was born in New Jersey and raised in this country and in Iran, now lives in Menlo Park. She has Muslim roots on her father's side and Jewish ones on her maternal side. She contends that the two cultures actually have a great deal in common.

"Both traditions come from the same part of the world," she says in an interview. "The women wear similar head coverings. Beyond the physical, there are so many cultural similarities, especially with women. I found myself being just as comfortable in the same kind of way in the Moslem culture as I do or did in the Jewish culture. You have the same kind of superstitions, admonitions, guilt."

Though she's against the veil and the general inequities for women that she perceives in both religions, she sees value in preserving the traditions.

"That's not to say we should carry all of our culture like a sack on our back," she says. "There are parts of both cultures that I don't agree with, but we should open ourselves and our children."

Since the 1979 revolution in Iran, which brought the Ayatollah Khomeini to power, her Muslim and Jewish relatives have shared the experience of exile.

"`Diaspora' is a word I use it not only for my Jewish relatives but also for my Iranian relatives," she says.

Schooled in New Jersey, New York and Boston, Pari spent all of her vacations in Iran until the revolution. The last time she saw Iran was August 1978.

"I didn't think I was leaving for the last time. I thought I was just coming back to the States for a few months."

Once-prominent industrialists in Iran who produced everything from antibiotics to nail polish, Pari's family can't return to Iran under the present regime. They sued the Iranian government to reclaim their property, confiscated by the theocracy.

Ironically, it was the revolution that allowed Pari to become a writer.

"I might have been neatly placed as a housewife," she said. "The revolution forced me to take a good look at my life."

"The Fortune Catcher" is a gorgeous first effort, full of rich, poetic prose and dramatic intrigue. It is in part a cautionary tale about fanaticism.

Maman Bozorg uses Islam to justify her own agenda. Though a non-religious Israeli Jew, Amir, the friend of Layla's husband, is another kind of fanatic — obsessive about his own sexual desires.

In "The Fortune Catcher," the fanatical matriarch Maman Bozorg remembers how the Shah's police shamed her mother by ripping off her chador. (The veil worn in Iran was outlawed by the Shah and brought back under Khomeini.) Her mother later dies of pneumonia from obsessive ritual bathing.

"The doctor said it was the pneumonia that killed her, but I will always think of Reza Shah as her murderer and my mother's death as another casualty in his march away from the laws of God," Maman Bozorg says.

The revolution left the author wary of religious orthodoxy, but she still maintains a cultural connection to both faiths. She observes both Pesach and Norooz, the Persian new year.

"After my experience with Iran, my attitude about organized religion is mostly negative," she says. "I've seen so many misinterpretations of religion in a theocracy.

I've seen people who use religion to carry out their own ideas."

Nevertheless, she says, maintaining one's culture in exile is important.

"It's easier to turn your back and become something new, what we call American, which is a generic term that is really used more by people who don't understand what America is made of," she says. "Americans are immigrants. More and more that's the case. It's sort of a cop-out to deny that."