James Joyce's Leopold Bloom--the atheistic Everyman of Ulysses, son of a Hungarian Jewish father and an Irish Protestant mother--may have turned the world's literary eyes on Dublin, but those who look to him for history should think again. He could hardly have been a product of the city's bona fide Jewish community, where intermarriage with outsiders was rare and piety was pronounced. In Jewish Ireland in the Age of Joyce, a leading...