Publication launched on the occasion of the CGIAR's 40th anniversary. The content focuses on the impact of CGIAR's research from 1971 to 2011. The evidence summarized in the report was gleaned from a large literature on research impacts. It bears eloquent testimony to the CGIAR's growing commitment over the last decade to rigorous impact assessment. Certainly, it shows that the CGIAR founders' early confidence in agricultural science was well placed. But more importantly, the evidence provides grounds for continued confidence, as CGIAR researchers and partners build on past successes to confront the acute development challenges of the 21st century.