This introductory chapter sets the scene for the present volume on cooperation and coalitions in the climate change negotiations. Coalitions – understood here as cooperative efforts between at least two parties to obtain common goals – come in many forms and shapes. Although central to multilateral negotiations, they have received surprisingly little academic attention. We review research on coalitions, with a focus on the climate change negotiations. Our review shows that we still have a poor understanding of coalition formation, maintenance, and effectiveness. We then outline how the various chapters of this volume address this gap and contribute to our understanding of coalitions in multilateral (climate) negotiations.