Wittgenstein's Tractatus Logico-Philosophicus, first published in German in 1921 and in English translation in 1922, is one of the most influential philosophical texts of the twentieth century. It played a fundamental role in the development of analytic philosophy, and its philosophical ideas and implications have been fiercely debated ever since. This new translation improves on the two main earlier translations, taking advantage of the scholarship over the last century that has deepened our understanding of both the Tractatus and Wittgenstein's philosophy more generally, scholarship that has also involved discussion of the difficulties in translating the original German text and the issues of interpretation that arise.