Since antiquity until the beginning of the eighteenth century, the notion of lipids was limited to olive oil, at least in the Western world. Toward the end of that period, this concept was extended to the distinction among oils, greases, and waxes. It is only starting from the works of the great French chemist Michel Eugene Chevreul (Figure 1.1), founder of the science of lipids in 1823, when appears a classication of the “fats.” They were distributed in six groups dened by their physical property (mainly distillation), an important chemical property (saponication), and also according to the nature of the components of fatty substances. Broadly, this rst classication remains the model of those accepted still today.