The belief that old–age mortality is intractable remains deeply held by many people. Remarkable progress, however, has been made since 1950, and especially since 1970, in substantially improving survival at older ages, even the most advanced ages. The pace of mortality improvement at older ages continues to be particularly rapid in Japan, even though mortality levels in Japan are lower than elsewhere. The progress in improving survival has accelerated the growth of the population of older people and has advanced the frontier of human survival substantially beyond the extremes of longevity attained in pre–industrial times. Little, however, is known about why mortality among the oldest–old has been so plastic since 1950. The little that is known has largely been learned within the past few years. New findings, especially concerning genetic factors that influence longevity, are emerging at accelerating rate.