Across the globe, environmental protection is in need of strong governance arrangements: arrangements that comprise effective environmental laws and regulations, a functioning administration and an independent judiciary. Courts, often perceived as the third pillar of power alongside the legislative and executive functions of the State, have an important role to play in defending, upholding and (for judicial activists) creating an environmental rule of law. At the same time, many courts and their judges face significant challenges in doing so effectively. This volume looks at the possibilities and limitations that courts and judges encounter in protecting the environment. Norms that seek to protect the environment, and the common values it represents, are widely dispersed. We find them in thousands of domestic laws and regulations; we find them in international and regional treaties and unwritten customary laws. Sometimes we do not find them at all.