EU environmental legislation can be characterised by the vast amount of rules embedded into directives, regulations and decisions, its related inaccessibility and incomprehensibility, and its broad mix of regulatory instruments ranging from traditional permits to market-based approaches and labelling. Moreover, the rise of very complex problems like nanotechnology and climate change poses challenging regulatory questions to the EU legislator. Typical characteristics of the environmental domain, like ecological varying circumstances across countries, technical complexities related to finding proper solutions for the protection of the environment, and diverging needs and preferences among EU Member States, have furthermore contributed to all kind of flexibility arrangements in EU environmental legislation in order to enable the fine-tuning of rules towards specific ecological, cultural and economic circumstances. Legislative choices in the field of the environment are primarily policy choices, resulting from the political process involving the EU Commission, European Parliament and Council. While such choices can and should be discussed by political scientists and economists, this book is aimed at developing fresh insights by allowing environmental lawyers to analyse and discuss trends and choices in the field of environmental legislation. Hence, this book puts a legal perspective on the environmental regulatory action that the EU legislator undertakes, and particular attention will be given to the consequences of EU legislative choices for Member States’ obligations. While EU environmental regulation continues to expand, national governments of EU Member States struggle with the implementation of the vast quantity of EU legislation.