Timothy Williamson is the Wykeham Professor of Logic at Oxford University and Whitney Griswold Visiting Professor at Yale University. He was previously Professor of Logic and Metaphysics at Edinburgh University, and has been Visiting Professor at MIT, Princeton University, University of Michigan, and the Chinese University of Hong Kong. His books include Identity and Discrimination, Vagueness, Doing Philosophy, Knowledge and its Limits, Modal Logic as Metaphysics, and Suppose and Tell.