Fatty acids and their chemical derivatives have a place in almost every phase of modern living. They add wanted qualities to foods, pharmaceuticals, cosmetics, and other personal products. They improve the performance of paints, plastics, lubricants, textiles, and rubber products. Because their function is mainly to modify other well known materials, they are generally unknown to the ultimate user. Yet the "spread" of a margarine and the "slip" of a shoe-polish may originate with fatty acids.

The production and use of fatty acids is a clear-cut chemical partnership between Nature and man. Initial chemical synthesis takes place in the fields and farms and forests where the chain-like chemical structures of fats are built up.

These fatty chemical structures may be of vegetable or animal origin, each with characteristic properties reflecting its particular source. When used for nourishment fats are generally consumed with chemical change but, industrially raw fats are only at the beginning of the series of chemical processes needed to extend their usefulness into many fields.