Agricultural research and development (R&D) has reduced poverty by making food more abundant and cheaper. It may also have affected the variability of agricultural production, prices, and incomes—but food price variability is less important to richer people. Recent evidence of a slowdown in agricultural productivity growth, combined with the rise of biofuels, foreshadows a reversal of the past trend of rising agricultural abundance and a corresponding increase in vulnerability of a greater number of poor people to price variability. This chapter explores the role of agricultural R&D and related policy in contributing to or mitigating the consequences of variability in agricultural production. It emphasizes the implications of a slowdown in agricultural productivity growth in the face of a growing global population, combined with the rise of biofuels and changing climate, and the potential for agricultural innovations to address the attendant challenges to global food security.