The Volatility Surface"I'm thrilled by the appearance of Jim Gatheral's new book The Volatility Surface. The literature on stochastic volatility is vast, but difficult to penetrate and use. Gatheral's book, by contrast, is accessible and practical. It successfully charts a middle ground between specific examples and general modelsachieving remarkable clarity without giving up sophistication, depth, or breadth." Robert V. Kohn, Professor of Mathematics and Chair,