Human Aggression, War and Genocide explores sociopolitical phenomena through the lens of psychoanalysis and neuroscience, concentrating on concepts like aggression, leadership, and the psychology of ethnic, national, religious, and ideological large groups. Drawing inspiration from the famous " Why war?" exchange between Albert Einstein and Sigmund Freud that examined the psychological roots of war and violence, the authors expand on that discussion to examine racism, large-group dynamics, chosen traumas and chosen glories, and the relationship between leaders and their followers. Offering psychological analysis and insight into historical and contemporary conflicts, including the Russia-Ukraine and Israel-Hamas wars, they provide novel insights for understanding the psychological conditions that lead to large-scale human aggression, war, and genocide.