This text examines the theory and methods of quantitative genetics and presents case studies that illustrate the many ways in which the methods can be applied. The author brings together current theoretical and empirical studies to show how quantitative genetics can illuminate topics as diverse as sexual selection, migration, sociality and aggressive behaviour. Nearly half of the chapters focus on conceptual issues, ranging from quantitative genetic models to the complementary roles of quantitative genetic and optimality approaches in evolutionary studies. Other chapters illustrate how to use the techniques by providing surveys of research fields, such as the evolution of mating behaviour, sexual selection, migration and size-dependent behavioural variation. The balance of the volume offers case studies of territoriality in fruit flies, cannibalism in flour beetles, mate-attractive traits in crickets, locomotor behaviour and physiology in the garter snake, and cold adaptation in the house mouse. Taken together, these studies document both the benefits and pitfalls of quantitative genetics. This book aims to show the advanced student and scholar of behavioural evolution and genetics the many powerful uses of quantitative genetics in behavioural research.