The German text, with a facing English translation by P. M. S. Hacker Ludwig Wittgenstein's On Certainty collects the final notes of one of the twentieth century’s most influential thinkers, written during the last eighteen months of his life. These posthumously published fragments reflect on questions of knowledge, doubt, and belief. They offer a distinctive perspective on Wittgenstein's late philosophy, and contain many remarks which have greatly influenced epistemological debate in the ensuing decades. This new translation by P. M. S. Hacker offers a clear and improved rendering of the original German, restoring features of the manuscripts that are essential for understanding the text. Presented in a facing-page German–English format, the edition is clear and readable for both students and scholars, includes a detailed introductory essay on the genesis of the text, and benefits from extensive textual notes that support deeper engagement with Wittgenstein’s arguments. The text also includes several appendices with new translations of select excerpts from other late Wittgenstein manuscripts with reflections on knowledge, belief, doubt, and certainty. This definitive translation and edition of On Certainty enables readers to engage thoughtfully with Wittgenstein's final thoughts on the limits of doubt and the grounding of belief. Enhanced by Hacker's expertise, it is an invaluable resource for those studying epistemology, philosophy of language, or Wittgenstein's later work