This issue of Dermatologic Clinics will focus on four aspects of pigmentary disorders:: 1) the basic concepts of pigmentation, 2) hypermelanoses, 3) hypomelanoses, and 4) pigmentary disorders around the world. Some key articles included are on the origin, clinical presentation, and diagnosis of hypomelanotic skin disorders; hypomelanotic conditions of the newborn and of the infant; the evolutionary and social aspects of skin color; and pigmentary disorders in western countries.