This chapter contains information about the definition of the somatotype as a method to quantify the shape and composition of the human body, providing a quantitative summary of the current physique. It specifies which methods and formulas are used to calculate the three components of the somatotype: endomorphy (adiposity), mesomorphy (muscular and bone development), and ectomorphy (thinness). It then specifies how to classify the somatotype into thirteen established categories and interpret them, and shows how to calculate the X and Y coordinates of the somatopoint to graphically represent the somatotype on a somatochart. Information is included on how to calculate the average somatotype of a group, how to calculate the differences in the somatotype between a subject and a group, how to calculate the homogeneity of the somatotype within a group, and how to calculate the differences in the somatotype between one group and another. Finally, the issues to be considered in the application and interpretation of the somatotype are specified.