This edited volume addresses the environmental and cultural underpinnings of the kind of social conflict that spawned the origins and elaboration of ritualized human and animal sacrifice in Mesoamerica. The chapters variously document the place of cultural evolution and social complexity in the origins and elaboration of ritual human sacrifice, cannibalism, and trophy-taking across a broad spectrum of Mesoamerican cultural and social contexts that first saw the light of day before 2600 BCE, and rapidly developed and proliferated across the Mesoamerican world in the centuries to follow. They study the developments in sacrifice rituals through the centuries into the first millennium CE, when the Mexica Aztec and their allies had elevated ritual human sacrifice such that they produced a plethora of sacrificial acts, modes and manners of death, and associated deities to articulate the necro-cultures and blood-tribute of the times. The chapters further study present-day rites of Amerindian communities from throughout Mesoamerica that include paying homage to the deities of earth and sky through sacrifice and consumption of animal surrogates. The interdisciplinary effort undertaken by this international cadre of scientists, including anthropologists, bioarchaeologists, art historians, ethnohistorians, iconographers, and religious studies experts provides a particularly rich forum for launching an interrogation into the role of conflict, environment, and social complexity in the emergence and persistence of ritual violence and human sacrifice in the Mesoamerican world.