The life table of a population gives information about differences in age at death between the members of the population. These differences arise from the relative effects of genetic and environmental factors. The shape of the life table may provide information about the genetic variability in the population, the range of environmental factors that impinge on the population or the incidence of random events in the lifetimes of different individuals. A problem of some interest to population biologists is the evaluation of the relative effects of genetic and environmental components on the evolution of the life table. The resolution of this problem requires, first of all, determining some measure of the shape of the life table as a function of the age-specific mortality and fertility of the population. The analysis of the life table which this note describes is based on a new demographic parameter, the entropy of a population, introduced in population biology [1]. This parameter is a measure of the convexity of the life table. We observe that the three theoretical life-history curves [2, 3] can be characterized in terms of the maximization of our entropy parameter subject to simple constraints on the stable age distribution. This note is not concerned with the evolution of the life table. To do this we need to make some hypothesis concerning the genetic and environmental mechanisms that operate to determine the life history of a population. This aspect is discussed in a companion article [4]. An interesting application of our entropy parameter to the study of male-female mortality patterns is given in [5]. Let l(x) be the probability that an individual born at age zero survives to age x and let re(x) denote the age-specific fecundity. The net reproductive rate R o is given by