Obsessed with its beauty, humbled by its flaws, humans are covered by a unique ultra-thin shield that instantly defines and shapes the body living inside it. Now, National Geographic invites you on an in-depth adventure revealing not just the science but the vital cultural meanings we attach to this largest of all human organs. A trip back in time explores the evolution of human skin - and the rainbow diversity of skin color today. Cutting-edge research unveils the role skin plays in human sexual attraction. And we go beyond biology to trace the influence of skin on our perceptions of race, our skittishness about nudity and the intriguing riddle of personal identity.