This outstanding 4-part series is a rare and compelling investigation of our most basic emotions — fear, anger, love, and happiness — and the internal forces that can take humans from the brink of madness and obsession to the heights of ecstasy and euphoria. Bringing together powerful human stories with frontier science, the series looks at the primal emotions that we generate in our brains, and how nature and nurture combine to make us feel the way we do. See individual episodes for program descriptions