Why are some countries more willing and able than others to engage in climate change mitigation? This book's authors address this questionn by exploring climate and energy trajectories of seven key actors that play crucial and different rroles in global climate cooperation: Brazil, China, the European Union, India, Japan, Russia and the US. We map similarities and differences in domestic policies as well as the roles they play in the global climate negotiations. Moreover, to understand these similarities and differences we undertake a comparative analysis of the main drivers and barriers that shape cliamte and energy policy trajectories in each case.