Investigations of fraud and corruption encounter challenges ranging from their complexity and regulatory framework to availability of requisite expertise and management. Drawing on academic research and relevant investigative practice on common and international crimes, this book addresses the quality of administrative and criminal investigations of financial wrongdoing, based on the framework of the protection of the European Union's financial interests. It focuses on the tools available to investigators in terms of thinking strategies, hypothesis-formulation and -testing, consistency in decision-making, methods of evidence review and presentation, and investigative planning and strategy. The book discusses quality standards taking into consideration the human factor, particularly cognitive errors, and the role of established procedures and processes to mitigate limitations inherent in human cognition, as required by effective, quality-controlled investigations. Administrative and criminal investigations share challenges and cognitive hurdles discussed in other volumes of TOAEP's series on quality control in fact-work (Nos. 19 (Second Edition), 32, 33 and 38). The present volume analyses techniques, methods and theoretical perspectives relevant to fact-finders, investigation planners, and decision-and policy-makers. With a foreword by Susan E. Brandon, it offers chapters co-authored by investigators, justice practitioners, academics and the editors: Antonio Angotti, Simon Baechler, Charidimos Chaloftis, Olivier Coene, Marian-Vladut Cozma, Julius Dirma, Ivar Fahsing, Darren Frey, Pascal Hollevoet, Milanka Jug, Georgios Kougias, Anton Penneman, Paolo Proli, Anna Sagana, Jorick Schreurs, Carsten Stahn, Andon Tashukov, Judit Tátrai, Daniela-Simona Tatu, Kris Vandenberk and Tom Willems.