Biographer Deborah Baker was trolling the archives at the New York Public Library when she struck treasure -- nine boxfuls of essays, fiction, artworks and letters by Maryam Jameelah, a fundamentalist writer and thinker of some renown in the Muslim world.

By unpacking the boxes and piecing together Jameelah's complicated life, Baker untangled a nonfiction narrative as surreal as any fairy tale. The biography begins in Mamaroneck, N.Y., circa World War II. Like many Jewish children, young Margaret Marcus is haunted by Holocaust images. By the late 1940s, though, the sensitive girl takes up a new cause: the Palestinian plight.

Unable to reconcile her beliefs with the Zionism of her parents, Margaret renounces Judaism in 1949. Next, she embarks upon a spiritual journey that brings a new faith and even a new name: Goodbye, Margaret Marcus -- hello, Maryam Jameelah.

In 1962, a 28-year-old Jameelah leaves the United States forever. A Muslim holy man invites her to reside with his family in Lahore, Pakistan, where the convert lives out her years as an extremist and fiercely anti-Western pamphleteer. Baker's book dismisses Jameelah's dogmatic essays, though letters to her parents prove irresistible -- they're intelligent and witty and riddled with religious hypocrisy, not to mention bouts of psychotherapy and mental illness.

The story is so engrossing it's too bad the writing has a disorienting quality. There's a stiffness, an academic detachment, about the history and cultural criticism authored by Baker. On the flip side, Jameelah's letters are swift, gossipy, confessional. If only the book contained more of those.