Banks and other financial institutions play a fundamental role in any economy. They have a correspondingly crucial role to play in achieving sustainable economic development. This work explains how they can contribute and the steps to take. The first part sets the context of environmental imperatives and the responses of governments, business and financial services. Part Two examines the initiatives already under way, and what else is feasible. Part Three argues that more far-reaching change and revitalization of the economic system is needed and then describes how this can be achieved by the financial sector.