New data show plateaus and even declines in rates of incidence and mortality due to melanoma among some age groups. Increased rates persist among older men, creating needs for health care planning. Early detection presents a paradox: screening activities, which may be more prevalent among those with higher socioeconomic status, may both increase incidence and decrease mortality (by diagnosing melanoma earlier and through the removal of precursor lesions). Studies of the development of nevi show that they are robust risk markers for melanoma and share some epidemiologic features with melanoma. Multiple primary melanomas develop in 5% to 10% of subjects with melanoma and may reflect genetic predisposition. Combined analyses and methodologic studies have refined estimation of the effects of risk factors.