This volume is the result of a symposium entitled "Variation in Life Histories: Genetics and Evolutionary Processes" sponsored by the Program in Evolutionary Ecology and Behavior of the University of Iowa and held in Iowa City on October 13 and 14, 1980. Prompted by a recent upsurge of interest in the evolution of life histories, we chose this topic because of the obvious association between life history traits and Darwinian fit ness. If such an association were to be fruitfully investigated, it would require the closer cooperation of population and evolutionary ecologists and quantitative...