This book demonstrates the crucial importance of "approach" in shaping the outcomes of research and development, and distils lessons learned on what works, where and why. It is enriched with examples and case studies from five benchmark sites in Ethiopia, Uganda, Kenya and Tanzania, whose variability provides the reader with an in-depth knowledge of the complexities of integrated NRM in agro-ecosystems that play an important role in the rural economy of the region. It is shown that the struggle to achieve sustainable agricultural development in challenging environments is a complex one, and can only be effectively achieved through combined efforts and commitment of individuals and institutions with complementary roles.