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You are! People are built from elements: mostly oxygen, carbon, hydrogen, and nitrogen. And you have a lot in common with the paper in a book—it is a network of carbon, hydrogen, and oxygen atoms, together called cellulose. Everything we see is chemistry, as are some things we do not see. The air is mostly nitrogen molecules, some oxygen molecules to breathe, and more of the greenhouse gas carbon dioxide than scientists think is safe. Chemistry is also about how arranging and connecting elemental building blocks differently can create such varied entities as a person, a book, and air. It is about how and why some atoms of elements connect with each other and with other elements. It is also about why some elements are reluctant to interact at all. Chemistry is what separates inactive substances, such as dust and rocks, from living organisms, which are animated by complex interactions. Such knowledge has improved life for many. But it has also caused pollution that counteracts those benefits in numerous ways. Chemistry could remedy the problems caused by pollution—but it must be used wisely.