Touch is the sense that makes us human. It defines our experiences, shapes our sense of self, and bonds us together. It is the first sense to start working in utero. If you are deprived of the sense of sight or hearing from birth, you will still be able to live a rich and fruitful life. But depriving a baby of the sense of social touch has dramatic consequences: if they are not regularly touched and cared for, they will develop higher lifelong levels of stress, their personality will be more fearful, and they will be less likely to explore the world. In Touch: The Science of Hand, Heart, and Mind, David J. Linden, professor of neuroscience at the Johns Hopkins University School of Medicine, shows how this overlooked sense actually shapes all our lives, from why brushing fingers with a waiter will make you leave a larger tip to why choosing a warm drink in a job interview improves your chances.