This article examines the evolution of the novel in the United States using a remarkable new source, the Ngram database. This database, which spans several centuries, draws on the 15 million books that Google has scanned. It allows researchers to look at year-to-year fluctuations in the use of particular words. Using one of the available filters, the article is based on English-language books published in the United States between 1800 and 2008. But making sense of these data requires a framework. That framework is provided by the four periods that emerge from much recent writing on the novel. Four epochs—the sentimental era (1789-1860), the genteel era (1860-1915), the modern era (1915-60), and the postmodern era (1960-)—define the evolution of the novel and, more broadly, changes in American society and values. The article argues that a study of key words drawn from the Ngram database confirms the existence of these periods and deepens our understanding of them.