What does it mean to be Jewish? Is Judaism strictly a religion, or has it become a culture? Can it have elements of both? What is the role of Judaism on the modern world's complicated stage? Jews of all backgrounds, from the orthodox to the secular, are asking these hard questions. Jeremy Rosen, a rabbi who leads a Persian Jewish community in Manhattan, is a thought leader in this constantly evolving dialogue. His new book, "Commitment and Controversy:...