This book is a successful attempt to identify quantitative methods for assessing the impact of CGIAR natural resource management research (NRMR). In doing so clearly and objectively, it provides a foundation for impact assessment for a wider set of research projects.

The first part examines the rise of NRMR and its relationship with research for productivity enhancement. It includes a detailed exposition of modelling of micro- and macro-level NRM innovations and their adoption. The second part examines seven contrasting NRMR impact assessment case studies, two covering NRM policy research issues and five on NRM challenges at farm level. The methods and results are described in sufficient detail to enable the reader to determine their efficacy in assessing economic, social and environmental impacts, and the returns to research investment made. The third part analyses the main lessons learned from the cases, and looks at the way ahead for NRMR impact assessment.

The main contributors to the book are economists, which flavours the methods used, the presentation of results and their analysis. Social impact is considered, but given insufficient weight. It is also difficult to discern the replicability and scaling-up potential of the CGIAR projects. No indication is given of the cost of impact assessment, or of the capacities required to carry them out. More discussion of the implications for project design would have been useful. Notwithstanding, this is an extremely useful book for researchers, research managers and development practitioners looking for ways to assess objectively the impact of research projects.