Charles Sanders Peirce (pronounced 'purse'), 1839-1914, was a many-sided genius and perhaps the most original thinker in the history of the United States. He is remembered today as a philosopher and as the founder of Pragmatism, the only philosophical movement initiated in the New World. However, he was trained in mathematics and chemistry, made his living making exacting measurements in astronomy and geodesy, published an experiment that is a classic in the history of psychology, developed a pioneering logic of probabilistic reasoning in the empirical sciences, and made contributions of fundamental importance to the revolutionary development of modern mathematical logic. In his own day, he had an international reputation among mathematicians and logicians as a founder of the logic of relations, as well as being known by astronomers and geodesists for his work in those fields. Nevertheless, he fell on hard times and, despite the efforts of his friend, William James, to revive his career, he died in poverty and obscurity. Though he gave several long series of lectures in philosophy and published several series of articles notable for their boldness and originality, he never completed a philosophical book. His voluminous unfinished manuscripts are a tangle of revisions and digressions, often highly technical.

After his death, Harvard University acquired his papers and an edition of them, in eight volumes, appeared from 1931 to 1958 (The Collected Papers, Harvard University Press). Interest in his philosophy has grown since then and is now strong not only in many parts of the world but among scholars in diverse disciplines. In particular, his ambitious though unfinished theory of signs has been adopted and applied by scholars in literature, cultural anthropology, art history, biosemiotics, and other fields. A new and more complete, chronologically arranged edition of his writings is under preparation by the Peirce Edition Project at Indiana University / Purdue University in Indianapolis. So far, seven volumes of the Writings of Charles S. Peirce have appeared (1982-2010, Indiana University Press) and twenty-three more are planned. Peirce's personal life has its tragic or pathetic mysteries, his scientific contributions are stunning by their multitude and variety, and his philosophical writings are an endless font of original ideas still being discovered, debated, and developed.