Private enforcement of competition law, in particular through damages actions, is recently one of the highly debated topics in European competition law. Arguments for private enforcement are based on the EU principle of effectiveness, while existing national substantive and procedural regimes applicable to damages may be ill-suited for the effective enforcement of EU competition law. However, the risk that the introduction of enforcement-oriented measures into national law is incompatible with private (civil) law is often underestimated or neglected. This book aims to reconcile both EU enforcement and private law perspectives through a detailed study of the English and Slovenian private law systems. Research on the compatibility of EU competitionenforcement- oriented measures with the private law regimes in England and Slovenia is used to argue that some changes to private law (based on proposals for effective enforcement) go too far and risk undermining the integrity of the Legal systems. This book already takes into account the 2014 Directive on antitrust damages actions.