Pope John Paul I
His controversial book, "In God's Name: An Investigation Into the Murder of Pope John Paul I" (1984), posited that Pope John Paul I, found dead at age 65 in his chambers barely a month after becoming pope in 1978, had been poisoned by secretive Masons who had infiltrated the Vatican and the Vatican Bank. Reviewers, and the Church, dismissed the book as groundless conspiracy theory. That said, the book made the New York Times Best Seller list for 15 weeks, was translated into multiple languages, and was repeatedly reprinted, selling over six million copies.