In the last ten years, the "comparative method" has been revolutionized by modern statistical ways of incorporating phylogenies into the design and analysis of comparative studies. The results of this revolution are particularly important in the study of animal behavior, which has relied on interspecific comparisons to infer universal trends and evolutionary patterns. The chapters of this edited volume consider the impact of modern phylogenetic comparative methods on the study of animal behavior and discuss the main issues that need to be considered in design and analysis of a comparative study, considers possible differences between the evolution of behavior and the evolution of morphology, and reviews how phylogenetic comparative studies have been used in certain areas of behavioral research.