This book examines selected actions and investments of the European Central Bank (ECB) from a climate and sustainability standpoint. Shedding new light on the topic from various angles - ethical, philosophical, political, economical and legal - it situates sustainability mainstreaming in the finance and investment field at all levels. The former ECB President Mario Draghi once said that he considered sustainable development and an intact environment to be human rights, and therefore enshrined in the EU Charter of Fundamental Rights. The acting ECB President Christine Lagarde added that the future path for the climate is uncertain, but it would remain within our power to influence it. However, with all that in mind the ECB's policy of buying assets as securities is often questionable. This volume analyzes these actions in connection with sustainability, and puts forward practical recommendations for improving the ECB's investment strategy on its way creating a sustainable financial market.