It's just possible that the body organ we know the least about is the one everyone can see (eew): our skin. Our epidermis and its companions are critically important to the body's defenses and overall health.
But our knowledge of the microbiome on our skin is very recent. That squeaky-clean thing? Not a good idea, it turns out, because it kills too much of the beneficial bacteria.
James Hamblin, physician and journalist, talked to a lot of people, investigated a lot of skin products, and skipped showers for a while to research his book Clean: The New Science of Skin. You may think of your skin and its maintenance in a whole new way.