The field of human body composition research is reaching a mature stage in its development. Quantifying the main body components is integral to the study of growth, as the assessment of human physical characteristics is important both in anthropological and medical fields. This article will focus on body composition methodology. Specifically, our attention is aimed at estimates of body fatness. An overview is first provided of the five-level model of body composition as it relates to measures of fatness. We then provide general concepts related to techniques for estimating body composition. Finally, we briefly discuss the measurement of adipose tissue distribution.