Music can move us, make us dance, or make us sad and nostalgic. When you are a neurologist as competent as Oliver Sacks, and especially a longtime music lover, how can you understand and describe this power? More brain areas are allocated to the processing of music than to that of language: man is therefore truly a musical species. And it is by deploying a gallery of portraits - from the surgeon who became a pianist after being struck by lightning to the penguin brother of Wittgenstein, passing by the mentally handicapped music lovers - that the author questions the relationships between the brain and music. Our musical dimension is described here in its breadth and depth, from a scientific, philosophical and spiritual point of view.