Achieving low-greenhouse and climate-resilient development in developing countries requires a significant mobilisation of finance from all sources: public, private, domestic, and international. The estimated financing gap for climate action in developing countries is significant. International public climate finance needs to be deployed more effectively to accelerate and scale up the mobilisation of private finance. This chapter provides context for the report. It presents the global challenge, both in the context of the USD 100 billion climate finance goal and beyond, and the fundamental questions this report seeks to address – what are the barriers to private finance mobilisation, and what are the opportunities to overcome them? – and the report’s scope and methodology for answering them.