This essay explores questions of language, thought, and difference through a close study of Walter Benjamin's translations of, essays on, and critical and creative adaptations of Marcel Proust's work. Benjamin said at one point that he was “poisoned” by his labors on Proust, and in a sense the infection never ended. At the same time Benjamin's thought is not only often distinct from Proust's but can also be entirely contrary to it. The details of this working combination of continuity and divergence invite us to think again about the tangled old issue of “fidelity” in translation.