Adopting an interdisciplinary framework, the book succinctly, yet accurately, traverses the full gamut of issues challenging the world today. This new edition deals more fully than the third edition with climate change, energy, and sustainable development. It also traverses a host of new challenges, such as drafting a new Kyoto Protocol, the Deepwater Horizon explosion and oil spill in the Gulf of Mexico, and the nuclear meltdown in Fukushima, Japan. It then clearly analyzes the legal responses, whether in the form of treaties, customary law, or soft law instruments.