By the late 1990s Green parties had entered national governments in five Western European countries - Finland, Italy, Germany, France and Belgium.This book analyzes the performance of Green parties in these five governments by answering the following questions: what are the political conditions under which Green parties have gained effective office? How do Green parties behave in government? What is the impact of Green parties on the policy performance of the national government? What is the effect of government participation on the electoral and organizational stability of the Greens? The book combines a broadly comparative analysis with case studies in order to provide a more thorough understanding of the differences and similarities of Green parties in coalition governments.