This book offers a systematic and multifaceted analysis of the Greens on the levels of political philosophy, political concepts, social movement, political parties, and political ideology. The originality of the book lies in the determination of the political philosophy of the Greens as left libertarianism. Such a determination of the Greens can already be found in the writings of Herbert Kitschelt, but while he only makes a cursory mention of it, this book offers a detailed elaboration of the points of contact between left-libertarianism and the Greens. The book also attempts to explain the acceptance of left-libertarianism by the Greens with social processes in Western Europe, the emergence of a new middle class and post-materialist values. At the same time, the book examines the relationship between the left-libertarian political philosophy of the Greens and the organizational structure of the Green parties, their relationship to the state, and to democracy.