Characterizing the variations of the human body shape is fundamentally important to many applications ranging from animation to product design. 3-D scanning technology makes it possible to digitize the complete surfaces of a large number of human bodies, providing much richer information about the body shape than the traditional anthropometric measurements. This technology opens up opportunities to extract new measurements for quantifying the body shape. Using the data from the first large scale 3-D anthropometric survey, the CAESAR project, we demonstrate that the human body shape can be represented by a small number of principal components. Principal Component Analysis extracts orthogonal basis vectors, called eigenpersons, from the space of body shapes. The shape of any individual person can then be expressed by the linear combination of the basis vectors. We demonstrate that some of these components correspond to the commonly used body measurements like height and weight and others indicate new ways of charactering body shape variations. We develop tools to visualize the changes of the body shape along the main components. These tools help understand the meaningful components of the human body shape.