This paper starts with the unsurprising observations that (1) having enough food available at national and local levels is necessary but not sufficient for ensuring that households have adequate access to food; (2) having adequate household access to food is necessary but not sufficient for ensuring that all household members consume an adequate diet; and (3) consuming an adequate diet is necessary but not sufficient for maintaining a healthy nutritional status. Recognizing that the links from food availability to access to consumption to nutritional status are not automatic, the challenge for policy makers and analysts concerned with achieving food and nutrition security is to understand how these variables are linked to one another, how closely they are related in various contexts, and what the important intervening variables are which affect the linkages among these variables. Unfortunately, however, our ability to understand the nature and extent of the relationships among these variables in detail has been hampered by a lack of information as well as by concerns over the appropriateness of the analytical approaches and indicators that have been used in empirical studies of these issues.