I am Associate Professor in Economics at the University of Oxford, and Wigmore Clarendon Fellow in Economics at Worcester College, Oxford. I have been at the Department of Economics, and its predecessor, since 1989. I work on theoretical models of pricing in imperfect competition, with a recent focus on price discrimination and its welfare effects. Previously I worked on the regulation of privately-owned utilities. I am the author, with Mark Armstrong and John Vickers, of Regulatory Reform: Economic Analysis and British Experience (MIT Press, 1994). I have papers in the American Economic Review, The Economic Journal and the Rand Journal of Economics, and am a former editor of Oxford Economic Papers, whose board I now chair. I teach Industrial Organization to graduate students, and for undergraduates I teach Microeconomics, Macroeconomics, the Economics of Industry and International Economics. I have also taught environmental economics.