Prior to the European Union (EU) 2004/2007 enlargement there were several predictions that this event would hamper progressive decision-making within the EU on environmental policy. It was believed that the new member states had adopted EU rules as a consequence of the EU's conditionality and consequently they would rather slow down the reform speed in the field after accession. In this book, Mats Braun offers an up-to-date account of how post-communist member states have handled policy initiatives in the field of environmental policy after accession. Using detailed case studies of how Bulgaria, the Czech Republic, Poland and Romania dealt with two different EU policy initiatives - REACH and the Climate-Energy Package - he explores whether social norms and the process of socialization can help us understand why the track record of new member states in the area of environmental policy is more varied than was originally envisaged prior to enlargement.