Paolo Mancosu is Professor of Philosophy at University of California, Berkeley. His main interests are in logic, history and philosophy of mathematics, and history and philosophy of logic. He is the author of <i>Philosophy of Mathematics and Mathematical Practice in the Seventeenth Century</i> (OUP 1996) and editor of <i>From Brouwer to Hilbert. The debate on the foundations of mathematics in the 1920s</i> (OUP 1988). He has recently co-edited the volume <i>Visualization, Explanation and Reasoning Styles in Mathematics</i> (Springer 2005). He is currently working on mathematical explanation and on Tarskian themes (truth, logical consequence, logical constants, nominalism) in philosophy of logic.