Following on from the CGIAR study by Evenson and Gollin (published by CABI in 2003), this volume provides up-to-date estimates of adoption outcomes and productivity impacts of crop variety improvement research in sub-Saharan Africa. The book reports on the results of the DIIVA Project that focussed on the varietal generation, adoption and impact for 20 food crops in 30 countries. It also compares adoption outcomes in sub-Saharan Africa to those in South Asia, and guides future efforts for global agricultural research.