We humans like to think of ourselves as rational creatures, who, as a species, have relied on intellect to survive. But many of the most important moments in our history—the outbreak of wars, the founding of religions, the fall of Rome—can't be properly grasped without understanding emotions. Drawing on psychology, neuroscience, philosophy, art, and history, Richard Firth-Godbehere vividly illustrates how our feelings and our beliefs about them have profoundly shaped us and the world we inhabit.