How do desires and fears motivate human sociability? What effect do these motivators have on reproductive, social and political behaviour? And, crucially, how might we understand them separate from preconceived notions of design or higher morality? Taking these questions as a focus, this book examines human evolution with the emphasis on sexual selection and the evolution of a number of human psychological processes. Exploring evolutionary, sexual and maturational processes, along with primate, fossil and geological evidence, Vannelli argues that human nature can be conceptualised as species-typical desires and fears, derived from sexual selection during human evolution, and that these are major motivators of behaviour. Presenting additional evidence from the anthropology of band societies, along with material from group behaviour, Vannelli highlights the importance of pair-bonding, friendship, alliance behaviour, vengeance seeking and interpersonal politics in social behaviour, providing a unique interdisciplinary framework for understanding human nature and the evolution of human sociability.