Ludwig Josef Johann Wittgenstein ( 26 April 1889 – 29 April 1951) was an Austrian-British philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language. He is considered by some to be the greatest philosopher of the 20th century. From 1929 to 1947, Wittgenstein taught at the University of Cambridge. In spite of his position, during his entire life only one book of his philosophy was published, the relatively slim 75-page Logisch-Philosophische Abhandlung (Logical-Philosophical Treatise) (1921) which appeared, together with an English translation, in 1922 under the Latin title Tractatus Logico-Philosophicus. His only other published works were an article, "Some Remarks on Logical Form" (1929); a book review; and a children's dictionary. His voluminous manuscripts were edited and published posthumously. The first and best-known of this posthumous series is the 1953 book Philosophical Investigations. A survey among American university and college teachers ranked the Investigations as the most important book of 20th-century philosophy, standing out as "the one crossover masterpiece in twentieth-century philosophy, appealing across diverse specializations and philosophical orientations".
