This potential revolution in sanitation has many benefits, including reducing inequalities, mitigating climate change and water scarcity, improving agriculture, and optimizing health. Author Chelsea Wald takes us on a wild world tour from a compost toilet project in Haiti, to a plant in the Netherlands that harvests used toilet paper from sewage, and shows us a bot that hangs out in manholes to estimate opioid use in a city, among many other fascinating developments. Much more than a glorified trash can, the toilet, Wald maintains, holds the power to help solve many of the world’s problems, if only we can harness it.