This text introduces the key elements of the dynamic, multidisciplinary field of conservation biology. In a concise format, the "Primer" highlights the material treated in detail in the 1998 textbook "Essentials of Conservation Biology", second edition. It incorporates background, theory, and examples in a lively and readable text that should appeal to a wide audience and stimulate interest consevation biology. The book provides perspectives on issues in the field such as sustainable development, the effectiveness of conservation laws and treaties, the design of conservation areas, classification of conservation threats, and strategies to save species on the verge of extinction.