In 2013, in vivo confocal Raman microspectroscopy of the skin is routinely being applied in human panelist studies. A growing number of research groups have access to the technology and knowledge; the technology is implemented on ve continents. Ever since the rst Raman spectra of skin was presented, it has been known that these spectra contain unique information on the chemical composition of the skin. The ability to measure the chemical composition of living biological tissues nondestructively is a valuable tool in the skin sciences. Raman spectroscopy has qualities that make it unusually attractive for such measurements. Especially, the ability to measure the chemical composition of tissues noninvasively at dened depths, using confocal optics (optical sectioning), is unique. Because of the complexity of biological tissues, Raman spectroscopy has only in the last decade begun to make signicant contributions in skin science. A 2008 review discusses the in vivo applications of Raman spectroscopy in the measurement of the composition of skin, including topically applied compounds and their effects on skin composition, in the context of pharmaceutical applications (such as transdermal drug delivery) [1].