This presidential address is keyed to the exhibition "All of Us Are Related, Each of Us Is Unique." It reveals that there are no biological barriers between the 5.7 billion human beings that today inhabit the earth. We all have the same ancestors and the genetic diversity of contemporary human populations reflects the paths followed by our ancestors in the course of human migrations over the past 100,000 years. I assert that there is simply no such thing as "white people", "black people", "yellow people", or the like, except as social constructs. In a world in which intergroup hostility has long been based on erroneous beliefs in biologically determined characteristics of so-called "races", our habitual way of thinking about how we relate to each other needs seriously to be re-examined.