Stemming from research of international experts in demography, epidemiology, gerontology, psychiatry, this book presents: a study of necessary conditions to compare several life expectancy computations in health, because current computation methods are different from one country to another; discussions of methods of interpretation of chronological life expectancy series; a survey of potential uses of life expectancy in health in order to allow sociosanitary planning; how to harmonise information collection and life computations.