Cutaneous malignant melanoma is one of the most rapidly increasing and highly fatal cancers in the world today. Current estimates suggest that 1 in 90-100 Caucasians will develop MM by the year 2000, and 20%-30% will eventually die of the disease. The cause of the epidemic of malignant melanoma is clearly increasing exposure to the sun from lifestyle and clothing habits that have changed over the past 50 years. The disease occurs primarily in preexisting nevi in sun-exposed sites in specific high risk populations who can be, and have been, defined. These are primarily middle- and upper middle-class Caucasians with blue eyes, brown or blonde hair, and fair skin, with predominantly indoor occupations who spend, or have spent, considerable time outdoors in leisure and other activities. The presence of a clearly definable cause (exposure to the sun) in specific risk groups, the ease of early detection by simple means, and the devastating outcome of late diagnosis make malignant melanoma an ideal model for teaching the basic tenets of cancer causation, development, and prevention to the public and professionals alike.