This guide has been conceived as a companion to students of international study programs, who are required to take courses in environmental law, to help them navigate their way through the subject matter. The target group is not limited to students with previous legal knowledge; it expressly includes those who are not law students but are studying law as a complementary subject. In a condensed manner, the guide provides an overview of the fundamentals and most significant developments of environmental law, focusing on international and European environmental law. This is done by deliberately making connections to German environmental law in order to illustrate and make comprehensible the interplay between international environmental law, European environmental law, and -- in referring to the German case -- national environmental law. Drawing on climate protection as an example of global significance, the relations between these three levels are explored in-depth and their foundations and development discussed.