Extreme value theory is concerned with probabilistic and statistical questions related to very high or very low values in sequences of random variables and in stochastic processes. The subject has a rich mathematical theory and also a long tradition of applications in a variety of areas. Among many excellent books on the subject, Embrechts et al. (1997) give a comprehensive survey of the mathematical theory with an orientation towards applications in insurance and ¯nance, while the recent book by Coles (2001) concentrates on data analysis and statistical inference for extremes.