Skin color is perhaps the most decisive and abused physical characteristic of humankind. This book presents a multidisciplinary overview of how and why human populations vary so markedly in their skin color. The biological aspects of the pigment cell and its production of melanin are reviewed. The functions of melanin in the skin, brain, eye and ear are considered, and the common clinical abnormalities of pigmentation, such as albinism, are described and illustrated. Detailed reflectance data from worldwide surveys of skin color are also presented. Next, historical and contemporary backgrounds of the phenomenon are explored in relation to the so-called color problem in society. Finally, the possible evolutionary forces that shape human pigmentation are assessed.