Based on new research results and practical findings, this revised edition text re-emphasizes the importance of agroecology as the discipline that provides the basic ecological principles for how to study, design and manage agroecosystems that are both productive and natural resource conserving, and are also culturally-sensitive, socially-just and economically viable. Agroecology goes beyond a one-dimensional view of agroecosystems - to embrace an understanding of ecological and social levels of coevolution, structure and function. However, ecological health is not the only goal of agroecology. In fact sustainability is not possible without preserving the cultural diversity that nurtures local agricultures. Stable production can only take place within the context of a social organization that protects the integrity of natural resources and nurtures the harmonious interaction of humans, the agroecosystem and the environment. The second edition incorporates new insights and concepts in the hope of helping guide agricultural students, researchers and practitioners to a deeper understanding of the ecology of agricultural systems that should open the doors to new management options more in tune with the objectives of a truly sustainable agriculture.