Irving Louis Horowitz is Hannah Arendt professor of sociology and political science at Rutgers University, and editor-in-chief of Transaction/society, the largest interdisciplinary social science research publication in the United States. Among his other honors is the privilege of studying with Abraham Edel at the City College of New York between 1947 and 1951. He has held visiting professorships at Princeton, Stanford, Wisconsin, and the University of California in the United States, and overseas appointments at the University of Tokyo, Buenos Aires, the London School of Economics, the Hebrew University in Jerusalem, and on several occasions, at the University of Buenos Aires. He is the author of The Idea of War and Peace in Contemporary Philosophy and Social Theory (1956, 1972); Science, Philosophy and the Sociology of Knowledge (1961); Ideology and Utopia in the United States (1976); and most recently, Communicating Ideas (1986)., H.S. Thayer is professor of philosophy, The City College and Graduate Center of the City University of New York. He was W.T. Bush Fellow in Philosophy, Columbia University (1947-1948), and has held a Guggenheim Fellowship (1970), National Endowment for the Humanities Fellowship (1974), and membership in the Institute for Advanced Study, Princeton (1974, 1982). His specialization is the history of philosophy and science and the theory of knowledge. He has published articles on Plato, Aristotle, and Greek philosophy, and is an authority on pragmatism and the work of Charles S. Peirce, William James, and John Dewey. His books include The Logic of Pragmatism (1952, 1971); Newtons Philosophy of Nature (1953); Meaning and Action: A Critical History of Pragmatism (1968, 2nd rev. ed., 1984).