In his book Clean, author and physician James Hamblin explores the history behind the human obsession with cleanliness and the colossal industry driving our current desire to scrub every inch of our bodies. At the same time, Hamblin details his voyage into a showerless life, which was not without a very smelly, greasy adjustment period. His friends swear he doesn’t smell or look visibly filthy, but if their word doesn’t convince you, Hamblin trots out science to explain his lack of funk and why his showerless routine—okay, he does rinse off quickly after a work out, but he hasn’t been sudsy in years—may not be unhealthy after all. Trillions of microbes cover our skin, creating a flourishing microbiome of good bacteria, and every time we lather up, we kill those little helpers en masse. These massive die-offs create room for harmful bacteria to set up camp, which triggers our bodies’ immune response in the form of nasty-looking, undesirable inflammation or irritation. To get to the truth about cleanliness, Hamblin consults a cast of characters—including dermatologists, microbiologists, allergists, immunologists, aestheticians, Amish people, venture capitalists and even some scam artists. The deeply-researched read leaves us wondering, is the future of skincare headed toward bolstering a healthy microbiome instead of obliterating it?