Ludwig Josef Johann Wittgenstein (April 26, 1889 – April 29, 1951) was an Austrian philosopher who worked primarily in the foundations of logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language.[1] His influence has been wide-ranging and he is generally regarded as one of the twentieth century's most important philosophers.

Before his death at the age of 62,[2] the only book-length work Wittgenstein had published was the Tractatus Logico-Philosophicus. Philosophical Investigations, which Wittgenstein worked on in his later years, was published shortly after he died. Both of these works are regarded as highly influential in analytic philosophy.[3]