Louis Armstrong was once asked to define “swing.” His response was—probably apocryphally—“if you have to ask, you'll never know.” But when it comes to defining and understanding capitalism, “you'll know it when you see it” answers do not suffice. Defining precisely what we mean by capitalism has never been easy. Capitalism is a “keyword,” to use Raymond Williams's term, a touchstone in our cultural and political debates. For Williams, keywords have “a history and complexity of meanings; conscious changes, or consciously different uses; of innovation, obsolescence, specialization, extension, overlap, transfer” (Raymond Williams, Keywords: A Vocabulary of Culture and Society [1976]). And there is good reason to think that, over the past generation, as capitalism has globalized, both surged and failed, and largely displaced its former rivals to the left, socialism and communism, the problems of precisely saying what we mean when speak of capitalism has only become more difficult.