This report of the High Level Group for Hydrogen and Fuel Cell Technologies sets out a vision for these technologies in future sustainable energy systems - improving energy security of supply and air quality, whilst mitigating climate change. The report recommends actions for developing world-class European hydrogen technologies and fostering their commercial exploitation. The High Level Group comprised key stakeholders from industry, the research community and public authorities. It was initiated by Vice President Loyola de Palacio and Commissioner Philippe Busquin, in association with President Romano Prodi.