The brain lies at the core of the human experience. It controls the smile of a baby, the complex calculations of a mathematician, the rage of a criminal, and the coordinated movements of an athlete. Neuroscience is the interdisciplinary study of the nervous system, whose ultimate goal is to understand brain and nervous system function and neurological disease at many levels. Neuroscientists combine a variety of approaches from the molecular to the systems level to approach this goal. The excitement of the field comes from the attempt to understand the organ that defines us as individuals, controlling our actions, generating our emotions, and holding our memories.