This book is addressed to scientists, researchers, development specialists and policy makers who deal with natural resources and agriculture in the developing countries. It aims to (1) provide evidence of the impact of natural resource management research (NRMR) in the CGIAR; (2) establish a methodological foundation for impact assessments of NRMR; and (3) draw up a set of lessons for future impact assessment studies. The book consists of three main parts. Part I (chapters 1-3) provides the definitional, historical, and theoretical background for NRMR impact assessment in the CGIAR. Part II (chapters 4-11) presents the methods and results of seven case studies on the impact of NRMR projects carried out in the CGIAR. Two summary chapters (12 and13) are presented in part III. The book has a subject index.