Between 1870 and 2010 an unprecedented explosion of material wealth transformed the globe, but that wave of prosperity failed to create a fully functioning and equal society. How did we manage to create an economic pie large enough for everyone to share, but then fumble dividing that pie up equally? Brad DeLong explores this question in his new book, Slouching Towards Utopia, which looks at the economic history of the twentieth century and why it matters today.