This chapter outlines what climate change adaptation is and what categories of adaptation can be distinguished. The chapter also discusses how adaptation and mitigation are related and how risks and uncertainties both underscore the need for adaptation but also make it difficult to develop adaptation policies. Other barriers to adaptation are discussed as well. The chapter then explains the lay-out of the book and draws some overarching conclusions, such as the conclusion that, although adaptation receives a growing amount of attention, both in practice and in academia, adaptation law still is emerging only slowly.