Without innovation, farmers would struggle to raise production and productivity. Innovation explains in part why more food per capita is produced in 2020 than in 1960, despite rapid population growth. Innovation increasingly contributes to agricultural growth: since 1990, most agricultural growth has come from rising (total factor) productivity, made possible by innovation. Technical innovations do not just drive production. They can raise the farm incomes of smallholders: in low-income countries, productivity gains in agriculture do more to reduce poverty than those in industry or services. Innovation potentially conserves resources and can make agriculture sustainable. In sub-Saharan Africa (SSA), agricultural innovation is especially important. This report brings together research on innovation by farmers, mainly smallholders, in SSA from Development and Economic Growth Research Programme (DEGRP) studies with the wider literature.