Although clustering -- the classifying of objects into meaningful sets -- is an important procedure, cluster analysis as a multivariate statistical procedure is poorly understood. This volume is an introduction to cluster analysis for professionals, as well as for advanced undergraduate and graduate students with little or no background in the subject. Reaching across disciplines, Aldenderfer and Blashfield pull together the newest information on cluster analysis -- providing the reader with a pragmatic guide to its current uses, statistical techniques, validation methods, and compatible software programmes.