Charles Sanders Peirce was the son of the eminent mathematician and Harvard professor Benjamin Peirce. The young Peirce attended Harvard University, where he studied science, mathematics, and philosophy. For 30 years he worked for the U.S. Coast and Geodetic Survey. Because of personal difficulties---he was overbearing and eccentric---he taught only briefly as a lecturer at Harvard (1864-65, 1869-71) and at Johns Hopkins University (1879--84). He wrote no books and published very little during his lifetime, mostly articles and encyclopedia entries, but many collections of his articles and unpublished papers have appeared. Peirce was a brilliant logician and creative metaphysician. His papers, many published long after his death, are of great importance in the philosophical literature.