This set of lecture notes contains basic theory in environmental and resource economics. It covers not only the traditional topics pollution targets and instruments, renewable and non-renewable resources, growth, trade, and valuation, but also the newer topics international aspects, stock pollution and tipping points. The lectures focus on the main concepts, models, and results in the core areas of environmental and resource economics, and form the basis for extensions, applications, and policy issues in the courses.The book is compact and can serve as a basic text for a course in environmental and resource economics at the advanced undergraduate level. It can also be useful as a reference text at the graduate level or for research. The mathematics in the main text is elementary, with more advanced mathematical analyses in the appendices. The book provides a precise account of the essentials in environmental and resource economics.