Margaret Marcus was a secular Jew in Mamaroneck, N.Y., before she grew fascinated with Islam and moved to Pakistan in 1962, taking the name Maryam Jameelah and becoming one of the pre-eminent Islamic voices, writing blistering critiques of Western materialism and secularism. Deborah Baker, who discovered the archive of Marcus’s papers in the New York Public Library, carefully reconstructs her life after she reached Lahore, using letters Marcus sent to her parents and articles she published in Islamic magazines. In The Convert: A Tale of Exile and Extremism (Graywolf, $23), Baker assembles the pieces of a singularly perplexing life that has proven stranger than fiction. Baker delivers not just a riveting and disturbing biographical account but an illuminating tale about the meeting of West and East and the role of women under orthodox Islam.