Monitoring and evaluation (M&E) of climate change adaptation (CCA) poses an assortment of thorny methodological challenges. Individually, none are unique to CCA, but together they represent a very distinctive conundrum facing practitioners and policy makers. Adding to this complexity further, climate change may be global in nature but its impacts, and how we respond to them through adaptation efforts, cut across scales, sectors, and levels of intervention. As investments in climate adaptation increase, organizations are seeking to measure, assess and understand an array of adaptation initiatives, and derive learnings to inform policy and praxis. This issue presents findings from many of the most important contemporary CCA program evaluation research initiatives. The chapters represent the most coherent and current collection of CCA M&E research in this emerging and important field, written by many of its leading experts. Filled with examples and insights in formulating coherent responses to methodological challenges, it will be of interest to M&E scholars and practitioners globally.This is the 147th issue in the New Directions for Evaluation series from Jossey-Bass. It is an official publication of the American Evaluation Association.