This volume, a shortened edition of Mr. van Heijenoort's internationally acclaimed From Frege to G?del: A Source Book in Mathematical Logic, 1879-1931 (HUP 1967), makes available in English the two most important works in the growth of modern mathematical logic. Heralded by Leibniz, modern logic had its beginnings in the work of Boole, DeMorgan, and Jevons, but the 1879 publication of Gottlob Frege's Begriffsschrift opened a great epoch in the history...