'We have long needed a volume that comprehensively, clearly, and systematically covers Boolean and fuzzy set methodologies. Schneider and Wagemann have filled this need with their book, and it will certainly play a central role in guiding research and teaching.' Gary Goertz, University of Arizona

'For relationships that can be viewed in terms of sufficiency or necessity, set-theory provides a powerful tool to model causality. QCA, in its various forms, provides a bridge between single case studies and quantitative analysis of linkages among interval-level or ratio variables across multiple cases by providing the tools to examine relationships in set-theoretic terms among dichotomies or concepts defined as fuzzy sets. This clearly written and comprehensive introduction to QCA, which insists on causal analyses that are explicitly intended to study possible multiple pathways to given outcomes, is must-reading for social scientists who wish to expand their methodological horizons and get away from the all too common 'throw as many variables as possible into the regression hopper and see which ones come up statistically significant' form of barefoot empiricism.' Bernie Grofman, University of California, Irvine

'This is the first volume that bridges the fundamentals of set-theoretic methods with the many ongoing innovations. A must for anyone aiming to exploit the full potential of the QCA toolbox.' Benoît Rihoux, Université catholique de Louvain, Belgium, and COMPASSS international network