"What do juggling, old bones, criminal careers, and human growth patterns have in common? They all give rise to functional data, which come in the form of curves or functions rather than the numbers, or vectors of numbers, that are considered in conventional statistics. The authors' book Functional Data Analysis (1997) presented a thematic approach to the statistical analysis of such data. By contrast, the present book introduces and explores the ideas of functional data analysis by the consideration of a number of case studies, many of them presented for the first time. The two books are complementary, but neither is a prerequisite for the other. The case studies are accessible to research workers in a wide range of disciplines. Every reader, whether experienced researcher or graduate student, should gain not only a specific understanding of the methods of functional data analysis, but, more importantly, a general insight into the underlying patterns of thought. Some of the studies demand the development of novel aspects of the methodology of functional data analysis, but technical details aimed at the specialist statistician are confined to sections that the more general reader can safely omit. There is an associated Web site with MATLAB and S-PLUS implementations of the methods discussed, together with all the data sets that are not proprietary.