Nostalgia is the defining emotion of our age. Political leaders promise a return to yesteryear. Old movies are remade and cancelled series are rebooted. Veterans reenact past wars, while the displaced across the world long for home. But who is behind this collective ache for a home in the past? Do we need to eliminate nostalgia, or just cultivate it better? And what is at stake if we make the wrong choice? Moving from the fight over Confederate monuments to the birth of homeland security to the mourning of species extinction, Grafton Tanner traces nostalgia’s ascent in the twenty-first century, revealing its power as both a consequence of our unstable time and a defense against it. With little faith in a future of climate change and economic anxiety, many have turned to nostalgia to weather the present, while powerful elites exploit it for their own gain. An exploration into the politics of loss and yearning, is an urgent call to take nostalgia seriously. The very future depends on it.