This book offers a critical exploration of the influential and pervasive belief that “we are our brains” (and that therefore he neurosciences will provide the key to all human phenomena). Since the 1990s, “neurocentrism” has become widespread in most Western and many non-Western societies. Advances, especially in neuroimaging, decisively bolstered it and helped justify increased funding for the brain sciences. Such a belief permeates many other contexts beyond basic research. Major national health agencies consider that “mental” illnesses are “brain disorders.” People diagnosed with some of those disorders advocate “neurodiversity” rights. In the human sciences, subspecialties such as neuroanthropology, neuroaesthetics, neuroeducation, neurohistory, neurolaw, neurosociology or neurotheology quickly professionalized. Dubious businesses, aimed for example at building neuroimaging lie detectors, selling (“neuromarketing”), or promoting wellbeing thanks to regimens said to target the brain (“neurobics”), became successful. The media has showered attention on all things “neuro,” and novels and films rehearsed the challenges of seeing persons as “cerebral subjects.” Skeptics have reacted to the “neurohype,” and spoken of neuromythology, neurotrash, neuromania or neuromadness. The neurocentric view of the human is not hegemonic or monolithic, but embodies a powerful ideology that is at the heart of some of today’s most important philosophical, ethical, scientific and political debates. Why We Are Our Brains critically explores the internal logic of such ideology, its genealogy, and its main contemporary incarnations.