The author summarizes and reviews the available scholarly literature on the environmental state. He describes the main research issues, gives an overview of different conceptualizations and definitions of the environmental state, and synthesizes the main findings on the patterns, causes, and consequences of state interventions on environmental issues. Based on the review a set of outstanding research issues are identified. In conclusion, the main argument is that these key issues in environmental state research can only be resolved with further empirical studies, with the overall goal of providing a better model of the political economy of the environmental state.