Book excerpt: Cover -- Title -- Copyright -- CONTENTS -- PART I Pathways to the present -- 1 Envisioning evolution: representations of humanness and causation -- 2 Origin stories: the co-evolution of human anatomy and sociality -- 3 Losses and gains: economic and health transitions since the Neolithic Revolution -- PART II Plasticity, identity, and health -- 4 Thicker than water: blood and milk in human evolution -- 5 Risk and responsibility: power and danger in individualized approaches to preventive health -- 6 Difference as destiny: race, sex, and culture -- PART III Sex and gender -- 7 Choosers and cheaters: the sexual/reproductive conflict hypothesis -- 8 Hoe and plow, pig and cow: work, family, and gender stratification -- 9 Tale of two-spirits: constructing gender and sexuality, aptitudes and inclinations -- PART IV Conflict and violence -- 10 Savage empathy: sources of competitiveness and cooperativeness, greed and generosity -- 11 Why stratify? Inequality and interpersonal violence -- 12 Peace and war: patterns and prevention of violent intergroup conflict -- Appendix: Life expectancy rate calculations -- Index.