Courtenay, F. (1922). Physical beauty: How to develop and preserve it. Social Culture Publications. https://doi.org/10.1037/13553-001.

All of humanity appreciates the physical attractiveness of women. However, there is no definite benchmark for it. The contours and shapes that we would consider ugly and misshapen are beautiful to the barbarian. The main components of attractiveness, in the eyes of the semi-civilized man, are weight and body fat. Even the most civilized man has different personal estimates. But the accepted qualities of form, face, and figure that most people find attractive can be said to be the closest thing we have to a precise standard of beauty. A woman can be made attractive by proportion, color, delicacy, type, symmetry, the flash of the eye, the sweetness of the smile, and a million other things. Every lady has her own unique beauty, though some have a blend of several. Beautiful skin, finely curved hands, elegantly proportioned feet and ankles, wonderful hair, and a noble and appealing body all impose a responsibility on their owners—the responsibility of care and preservation. Physical, mental, and moral beauty are all forms of virtue. It is as necessary to humanity as faithfulness and honesty. It is, or should be, the most ideal expression of the truth of the physical feminine being.