Only a few millimeters of skin separate our bodies from the dangers of the outside world. Yet skin’s multilayered design provides us with the perfect combination of strength, flexibility, and durability. Unlike any spacesuit or body armor designed by man, this protective covering is alive, constantly repairing and renewing itself.

You have perhaps heard that “beauty is more than skin deep.” While that is certainly true, the skin itself is beautiful and tells us a lot about people. For example, we recognize one another mostly by the skin on our face.

The skin’s blood supply and facial muscles even permit us to tell on sight when people are happy, sad, angry, or embarrassed. The skin is the largest organ in our body (weighing about 10 pounds [4.5 kg] in the adult) and covers the entire surface of our body, including our eyes, where the skin covering is conveniently transparent. Being on the surface, skin is the most accessible organ of our body, and thus must be marvelously resistant to our vain efforts to “improve” it with pigments, chemicals, punctures, and tattoos. Read more