Humans have traditionally been defined as rational, thinking beings, and the common name we have given ourselves proudly proclaims this: “sapiens.” But just as distinctive as our undeniable intellectual sophistication is our social nature—the deep need for community and belonging that continually drives us to seek contact and identification with our fellow humans. Our mind is both individual and collective, particular and tribal. And that collective nature can lead us to unity as well as to struggle and conflict.This book presents, in a manner that is both accessible and rigorous, the advances that psychology, neuroscience, and the social sciences have made in understanding that essential trait of human nature: sociability. Throughout its pages, it addresses topics such as the forms of human attachment, social identity, and the psychological roots of intergroup conflicts, empathy, collective emotions, and the neurobiology of social bonds.The final chapters show us how understanding our social mind can help us better comprehend pressing contemporary issues, such as political polarization, waves of collective outrage, and the spread of irrational beliefs and fake news in the digital environment.