For the past several decades, politicians and economists thought that high levels of inequality were good for the economy. But because America's middle class is now so weak, the US economy suffers from the kinds of problems that plague less-developed countries. As Hollowed Out explains, to have strong, sustainable growth, the economy needs to work for everyone and expand from the middle out. This new thinking has the potential to supplant trickle-down economics—the theory that was so wrong about inequality and our economy—and shape economic policymaking for generations.