ABSTRACTThe forces of mortality are the prime determinants of longevity. Longevity is a basic consideration of gerontology and includes the life expectancy of the species, the average expectancy of survival at birth, and the average lifespan. In the history of the study of old age, for which the modern period began about 1930, there are no reports of the average lifespan for the students of aging. A survey revealed that the average lifespan of 28 special groups (15,000 individuals) was 68 years; this included an average of 68.01 years for 394 gerontologists during the same eras. These figures are comparable because the attainment of a particular status in a profession or vocation is evidence of survival to maturity. Comparison could not be made with data for the general population whose vital statistics begin at birth. The average duration of life for men whose work in part or in whole prior to the 20th century was in gerontology falls midway between the high level of 77 years for classical Greek authors and the low level of 51 years for revolutionary statesmen, and exactly between the levels of life duration for eunuchs and physical and medical scientists.