The words that Martin featured on his album come from Rumi’s “Masnavi,” a six-book epic poem that he wrote toward the end of his life. Its fifty thousand lines are mostly in Persian, but they are riddled with Arabic excerpts from Muslim scripture; the book frequently alludes to Koranic anecdotes that offer moral lessons. (The work, which some scholars consider unfinished, has been nicknamed the Persian Koran.) Fatemeh Keshavarz, a professor of Persian studies at the University of Maryland, told me that Rumi probably had the Koran memorized, given how often he drew from it in his poetry. Rumi himself described the “Masnavi” as “the roots of the roots of the roots of religion”—meaning Islam—“and the explainer of the Koran.” And yet little trace of the religion exists in the translations that sell so well in the United States. “The Rumi that people love is very beautiful in English, and the price you pay is to cut the culture and religion,” Jawid Mojaddedi, a scholar of early Sufism at Rutgers, told me recently.