Every one of us contains a billion times more atoms than there are grains of sand in the Earth’s deserts. If you weigh one hundred fifty pounds, you’ve got enough carbon to make twenty-five pounds of charcoal, enough salt to fill a saltshaker, enough chlorine to disinfect several backyard swimming pools, and enough iron to forge a three-inch nail. But how did these elements combine to make us human? All matter—everything around us and within us—has an ultimate birthday: the day the universe was born. This informative, eye-opening, and eminently readable book is the story of our atoms’ long strange journey from the Big Bang and the creation of stars to the assembly of planet Earth and the formation of life as we know it. It’s also the story of the scientists who made groundbreaking discoveries and unearthed extraordinary insights into the composition of life.