Why do you immediately click with some people while others just as inexplicably turn you off? Do people emit vibes? Is it possible to read a room? Are bad habits contagious? Kate Murphy, author of the international bestseller You're Not Listening, answers these and other fascinating questions in Why We Click, the first book that explores the emerging science and outsize impact of interpersonal synchrony, the most consequential social dynamic most people have never heard of. Interpersonal synchrony is the seemingly magical, yet now scientifically documented, tendency of human beings to fall into rhythm and find resonance with one another. Not only do we subconsciously match one another's movements, postures, facial expressions, and gestures; recent breakthroughs in technology have revealed we also sync up our heart rates, blood pressure, brainwaves, pupil dilation, and hormonal activity. The result is that emotions, moods, attitudes, and subsequent behaviors can be as infectious as any disease, and can have just as profound an impact on our health and well-being. Interweaving science, philosophy, literature, history, business management theory, pop-culture, and plenty of relatable, real world examples, Why We Click explains why being "in sync," "in tune," "in step," and "on the same wavelength" are more than just turns of phrase. From the bedroom to the boardroom and beyond, Murphy reveals with characteristic curiosity, concision, and wit how our instinct to sync with others drives much of our behavior and how our deepest desires--to be known, admired, loved, and connected--are so often thwarted in modern life.