The formal hierarchy of public law legal rules is being eroded and, as a result, is proving less and less useful as a framework for analysis. It is submitted that pluralist concepts such as legal dialogue and legal competition are far more useful for studying the reality of public law today. No longer is the formal hierarchy central, but the debate between the various actors at the various levels. The idea that EU law has primacy over national law, based as it is on the formal hierarchy of legal rules, now seems far too simple.This book on Pluralism in European Administrative Law, which is also published as the 2012/2 issue of the Review of European Administrative Law (REALaw), contains a selection of papers from the Second REALaw Research Forum that was held in Groningen, the Netherlands, on February 3rd 2012. Together, they provide a fascinating picture of the process of pluralism in the formation of law through legal dialogue and legal competition in European administrative law.