To the horrors of war and genocide in the twentieth century there were witnesses, among them Hermann Cohen, Emmanuel Levinas, Ernst Bloch, Leo Strauss, Franz Rosenzweig, Gershom Scholem, Walter Benjamin, Martin Buber, and Hans Jonas. All defined themselves as Jews and philosophers. Their intellectual concerns and worldviews often in conflict, they nevertheless engaged in fruitful conversation: through the dialogue between Zionist activism and heterodox forms of Marxism, in the rediscovery of hidden traditions of Jewish history, at the intersection of ethics and metaphysics. They shared a...