A revelatory synthesis of cultural history and social psychology that shows how one-to-one collaboration drives creative success. Weaving the lives of scores of creative duos—from John Lennon and Paul McCartney to Marie and Pierre Curie to Steve Jobs and Steve Wozniak—Joshua Wolf Shenk identifies the core qualities of that dizzying experience we call "chemistry." Revealing the six essential stages through which creative intimacy unfolds, Shenk draws on new scientific research and builds an argument for the social foundations of creativity—and the pair as its primary embodiment. Along the way, he reveals how pairs begin to talk, think, and even look like each other; how the most successful ones thrive on conflict; and why some pairs flame out while others endure. When it comes to shaping the culture, Shenk argues, two is the magic number, not just because of the dyads behind everything from South Park to the American Civil Rights movement to Starry Night, but because of the nature of creative thinking. Even when we're alone, we are in a sense "collaborating" with a voice inside our head. At once intuitive and surprising, Powers of Two will change the way we think about innovation.