The 30th anniversary of the signature of the German-Polish Neighbourhood Treaty (1991) is an excellent opportunity to reflect on Polish-German relations in terms of current challenges regarding environmental issues and the possibility of developing a joint strategy to counteract the progressive climate degradation (Polish-German Green Deal). The title of this publication, which refers directly to the EU?s strategy 'European Green Deal', demonstrates that, in addition to the long-term climate policy at the EU and national level, neighbourly bilateral relations are also important for slowing down the process of environmental degradation. However, the articles published in this book are not limited to the bilateral perspective. Part of the discourse focuses on issues related to the emerging climate crisis in the context of changes and trends in the development of international law, with a particular focus on European Union legislation, or exclusively Polish, or German law. The authors from Poland and Germany are academics, representatives of public institutions, local authorities, and non-governmental organizations. .