 Carl G(ustav) Hempel (1905–97), known as “Peter” to his friends, was born near Berlin, Germany, on January 8, 1905. He studied philosophy, physics and mathematics at the Universities of Göttingen and Heidelberg before coming to the University of Berlin in 1925, where he studied with Hans Reichenbach. Impressed by the work of David Hilbert and Paul Bernays on the foundations of mathematics and introduced to the studies of Rudolf Carnap by Reichenbach, Hempel came to believe that the application of symbolic logic held the key to resolving a broad range of problems in philosophy, including that of separating genuine problems from merely apparent ones. Hempel’s commitment to rigorous explications of the nature of cognitive significance, of scientific explanation, and of scientific rationality would become the hallmark of his research, which exerted great influence on professional philosophers, especially during the middle decades of the 20th Century.