Economic evidence has become an essential component of a successful competition law case, but questions surrounding the weight and value to be given to economic evidence have not been explored. This work provides competition law practitioners with a comprehensive legal and economic analysis of economic evidence in EU competition law. The book combines a theoretical perspective, an empirical approach and a practice-oriented focus. The theoretical perspective provides a thorough examination of the interaction between economic evidence and legal rules of evidence and causation. Its empirical approach provides the data necessary to understand the reality of economic evidence in selected key jurisdictions (such as the EU, France, the UK, and Germany) in the enforcement of EU competition law. Emphasising the law in action, the study combines quantitative and qualitative research from various legal systems, mapping the type of economic evidence presented in these cases and the way this was assessed. The book's practice-oriented focus provides a thorough understanding of the real-world process of legal evidence in this area. Each chapter dealing with different types of economic evidence introduces the reader to the forms that economic evidence usually takes and what it aims to prove, referring to examples from real cases and offering recommendations for practices and best principles. This is a complete and accessible reference guide, combining theoretical and practical insights.