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.