It is the human body's largest organ, yet most of us know little about it. On average, it is a mere one-twentieth of an inch thick, and yet it is the only boundary between the outside world and our vulnerable physiology. In many ways skin defines our identities, yet the subject is one that we are often reluctant to discuss. This program breaks commonly held taboos and preconceptions to get at the truth about skin: what it is, how it works, and why it matters to us so much. Beyond biology and medicine, the story of skin is the story of customs, cultures, and race. It is the story of who we are.