Emphasising the Q in qualitative comparative analysis (QCA), Roel Rutten presents QCA as a thoroughly qualitative method to help researchers learn from cases. He highlights that while Boolean expressions describing cross-case patterns are QCA’s most conspicuous element, they do not amount to causal explanations. Throughout the book, Rutten demonstrates how QCA’s interpretive logic pervades every step of a QCA study. He uses critical realism as a philosophical foundation to explain how QCA researchers develop their partial and perspectival knowledge of cases into Boolean expressions. Proposing multi-level sets as a way to acknowledge the diversity of social reality, Rutten criticises the use of fuzzy sets in QCA as a poor match to QCA’s threshold logic. Comprehensive and innovative, this book is a vital read for social science methods experts and users. It is also an important book for QCA experts and students looking for a deeper understanding of QCA.