This volume by Vaino Kannisto, former United Nations advisor on demographic and social statistics, is the first in the "Odense Monographs on Population Aging". It is fitting that Kannisto is the first author because the core set of data that built up to establishing the series, was assembled, tested for quality, and converted into cohort mortality histories by him. These data, which pertain to death counts and population counts by years of age, year of birth, and current year over the last four decades or in some thirty countries, permit estimation of death rates after age 80.Kannisto shows in this first volume that in developed countries since 1950 death rates among octogenarians, nonagenarians, and even centenrians have been reduced substantially. The novelty and magnitude of the observed mortality decline justify it being called a new stage in mortality transition. The pace of mortality improvement has accelerated in most countries since 1950. Kannisto concludes that 'the new transition may, barring unforeseen events, still continue for an extended period'.