The relationship between the world’s growing population and our ability to feed it at an acceptable level of nutrition is one of the most important and also one of the most controversial current global issues. This chapter studies some of the arguments which have been put forward, but the literature is so vast and complex that we cannot do more than sketch them in outline. Caution is essential, because any student of the relationship between population and resources soon realizes that simplistic explanations are potentially misleading, and perhaps even dangerous, if they spawn inaccurate forecasts and misplaced policy responses.