David J. Linden has devoted his career to understanding the biology common to all humans. But a few years ago he found himself on OkCupid. Looking through that vast catalog of human diversity, he got to wondering: What makes us all so different? Unique is the riveting answer. Exploring everything from the roots of sexuality, gender, and intelligence to whether we like bitter beer, Linden shows how our individuality results not from a competition of nature versus nurture, but rather from a mélange of genes continually responding to our experiences in the world, beginning in the womb. And he shows why individuality matters, as it is our differences that enable us to live together in groups. Told with Linden’s unusual combination of authority and openness, seriousness of purpose and wit, Unique is the story of how the factors that make us all human can change and interact to make each of us a singular person.