Derrida’s bristling new toy, deconstruction, shook up the intellectual world during the late Sixties, and the shock waves are still echoing today. Derrida was an Algerian Jew, a provincial upstart who conquered Parisian high theory with his thorny, baffling, volatile take on the philosophical greats. Judaism turned out to be surprisingly central to his approach: The Jewish sage Emmanuel Lévinas was one of Derrida’s heroes. “Are we Jews? Are we Greeks?” he brooded. “We live in the difference between the Jew and the Greek”: between Torah-inspired ethics and Gentile philosophy. Derrida’s bold flights were often obscure and wordy—but even those who didn’t read him started to say “deconstruct.”