This interesting book is a study implemented by the International Food Policy Research Institute (IFPRI), guided by the Standing Panel on Impact Assessment of the Science Council of the CGIAR, a panel responding to donor demands for evidence of the efficacy of international agricultural research.

Seven case studies make up the core of the book. Two at the national level, from India and China, illustrate impact through diverse pathways on a variety of constituencies. Five at the household and community levels, two from Asia, two from Africa and one from Mexico, used a sustainable livelihoods framework to aid comparability.

The discussions on methods in Chapters 1 and 2, especially on the balance of quantitative and qualitative approaches in assessing impact, are particularly valuable. The synthesis of findings and implications for future directions in studying the impact of agricultural research on poverty in the Chapter 10 is also well done. The editors contributed these three chapters and they deserve credit for the clarity and depth of discussion.

For me the book has two weaknesses: first, the study was compromised by budget limitations, in some cases existing quantitative studies were supplemented by new qualitative studies. Quantitative studies are best designed around the understanding gained from ex-ante qualitative work. Second, it would have added value to the book if the final chapter had addressed the design and costing of an impact assessment programme within an institutional budget, weighing the trade-off between the number of studies, the intensity of primary data collection in each and the lag time before impact assessments are made.