This article focuses on developments in pigmentary disorders that extend dermatologists' understanding of the field. Areas that are reviewed include the basic biochemistry, pharmacology, and physiology of the melanocortin system; melanosome development; genetic diseases associated with pigmentary disorders; pigmentary disorders secondary to systemic disease; drug-induced hyperpigmentation; environmental exposure to chemicals; and primary disorders of hyperpigmentation such as melasma and lentigines. Basic, clinical, and epidemiological research, along with a number of clinical case reports, were included in the review. This article also reports on the new health-related quality-of-life instrument (MELASQOL) that has been developed for women with melasma.