This book explores in detail the involvement of the European Union (EU) in international climate change negotiations from 1986 to present. This book is not so much about the EU as a leader in international climate politics, as it is about the EU as a negotiator. The two are not the same, even though these terms are often conflated. While the EU's leadership role has been largely acknowledged, this is the first book to offer a comprehensive discussion of the evolving role of the EU as a negotiator.