This section is from the book "The Manufacture Of Boots And Shoes: Being A Modern Treatise Of All The Processes Of Making And Manufacturing Footgear", by F. Y. Golding. Also available from Amazon: The Manufacture Of Boots And Shoes.
Structurally all feet are alike, but in form and measurement there exists great diversity. From three fundamental types of man, there are some seventy-two distinct races, each race having its characteristics. Even in a single race there are an infinite number of variations of the external form of the body. And so it is with feet; they differ in detail, and it is quite the rule to find a difference between the two feet of a single individual. Feet, however, may be classed, and their salient points of resemblance and difference compared and contrasted. This may be done in many ways - by tabulating the ratio the various parts of the lower extremities bear to the whole stature; by comparing the profile of various feet; by the plantar outline; and by measurement. All of these methods are useful in their way, and helpful in giving a better knowledge of the foot to be clothed.