From the wide ranging ‘Handbooks of modern statistical methods’ series, this book seeks to be a non‐exhaustive guide to the subject in a large and expanding field. The book is well laid out over 31 chapters each having its own introduction and conclusion, spanning the material in a logical manner aiding accessibility. Its main focus is on partitioning sets, and care is taken to explain the exploratory nature of the analysis in contrast with the predictive task of classification (i.e. it covers unsupervised rather than supervised classification).