Published online by Cambridge University Press: 01 October 2008
White dwarfs represent the endpoint of the evolution of the large majority of stars formed in the Galaxy. In the last two decades observations and theory have improved to a level that makes possible to employ white dwarfs for determining ages of the stellar populations in the solar neighborhood, and in the nearest star clusters. This review is centered on the theory behind the methods for white dwarf age-dating, and the related uncertainties, with particular attention paid to the problem of the CO stratification, envelope thickness and chemical composition, and the white dwarf initial-final-mass relationship.