This book examines the law and practice of the delegation of rulemaking powers to the European Commission. It combines legal doctrine with empirical research methods to bridge the gap between “law on the books” and “law in action” to fully appreciate the meaning and the impact of the changes post-Lisbon. The results of the empirical case study provide food for thought on how the current legal framework regime for delegated rulemaking by the European Commission could be improved. The findings seek to contribute to the academic and policy debates on this research topic that is likely to continue in forthcoming years.