David Lewis published a seminal paper on time travel in 1976, called ‘The Paradoxes of Time Travel’. It is a foundational piece that has impacted later discussions of time travel in analytic metaphysics. The paper was read at the APA in March 1976. His commentator was Jonathan Bennett, who expanded on his comments and sent the paper to Lewis. Lewis replied on 29 March 1977. The full version of the letter is reproduced below. (The letter was published as Letter 240, in Beebee and Fisher 2020 Philosophical Letters of David K. Lewis, Vol. 1, pp. 470-2, but with the small points redacted.)