More than ever before, environmental policy today has to be considered as a comprehensive inter-disciplinary approach. Complex environmental problems such as climate change or water shortages require the involvement of several control levels and various protagonists in strategies to find a solution. End-of-pipe approaches, which characterised environmental policy just a few years ago, do not go far enough. Effective environmental and sustainability policy links legal and economic instruments with new cooperative approaches. The IÖW analyses the problem contexts, develops and assesses environmental policy concepts and elaborates innovative solutions – always in close contact with the relevant protagonists from politics, industry and society.