Patrick A. Mello is a visiting scholar at the Willy Brandt School of Public Policy at the University of Erfurt and privatdozent at the TUM School of Governance of the Technical University of Munich. He is the author of Democratic Participation in Armed Conflict: Military Involvement in Kosovo, Afghanistan, and Iraq, winner of the 2015 Dissertation Award from the German Political Science Association. His articles have appeared in journals such as Foreign Policy Analysis, European Journal of International Security, and the British Journal of Politics and International Relations.

"Social phenomena can rarely be attributed to single causes. Drawing on set theory and the language of necessary and sufficient conditions, Qualitative Comparative Analysis (QCA) is a case-based research method that is ideally suited to capture causal complexity. QCA regards cases as combinations of conditions. It compares the conditions of each case in a structured way to identify the necessary and sufficient conditions for an outcome. While QCA has become increasingly popular and seen a substantial increase of applications across the social sciences and management, introductory textbooks have not kept pace with this development. In this textbook, Patrick A. Mello teaches students, scholars, and self-learners the fundamentals of QCA, research design, interpretation of results, and how to communicate findings. This concise and accessible textbook provides a hands-on introduction to QCA that will be ideal for use within a broader qualitative methods course and in intensive short courses"