The aim of this manual is to help policy analysts improve their understanding of the concept of food security and the problems related to it. Food security is defined as availability of, stability of and access to food by each human being. The food system, including the production and transformation of food, is studied with a view to understanding the causes of food insecurity. The manual then shows how international, macro-level and agricultural-sector policies affect the food system and how national and international policies that could improve food security can be identified.