Three major difficulties arise when thinking about the links between finance and growth. The first one is defining and measuring “financial development”. The second is extricating the crossed causal relationships between the development of financial systems and growth. And the third one address the definition of efficient public policies, policies that might result in a good balance between market imperfections and the costs of inefficient regulatory policies, but also likely to guide the financial development in order to maximize its impact on long-term growth. On each of these three problems, substantial progress has occurred over the last twenty years but important questions are still pending.