Adaptation to climate change is now widely recognised as an equally important and complementary response to greenhouse gas mitigation in addressing climate change. Adaptation consists of deliberate actions undertaken to reduce the adverse consequences, as well as to harness any beneficial opportunities. A wide range of adaptation measures can be implemented in response to both observed and anticipated climate change. How much adaptation might cost, and how large its benefits might be, are issues that are increasingly relevant both for on-the-ground projects, as well as in a global context where trade-offs might need to be considered between the costs of climate policies and the residual damages resulting from climate change. This chapter provides a context for examining adaptation costs and benefits, and discusses key issues related to the timing of adaptation decisions as well as how such decisions could be affected by the uncertainty surrounding the impacts of climate change. It also moves the discussion beyond cost estimation to examining market and regulatory mechanisms that can be used to incentivise adaptation actions. Such mechanisms have so far received little attention in the context of adaptation.