This working paper aims to inform the development community about the current state-of-knowledge and emerging thinking on the economics of adaptation and the application to development. The paper is based on a detailed review that has considered five key themes: The methods and framing for the analysis of adaptation; The types of adaptation applications and relevant economic support; Updated estimates of the costs and benefits of adaptation; Methodological aspects of adaptation appraisal; and Analysis of uncertainty in adaptation appraisal.