Abstract
Americans have been getting taller for more than a century, and within this century their life expectancy has risen markedly. Descendants of some of the immigrants who arrived from Europe early in this century have heads with shapes that differ from those of relatives back in the Old World. Before they were born head shape was assumed to be one of mankind's most stable features. These examples of population change reflect the fact that in America the quality of life has improved more rapidly and widely than elsewhere. Forensic anthropologists have been adjusting their identification techniques to compensate for these population changes. Among other things, they have used data collected in connection with the military programs to repatriate the American dead of World War II and the Korean War.