For four hundred years, Americans have been told to watch their language. For four hundred years, they haven’t listened.

From Puritan colonies where blasphemy could earn you a whipping to Civil War camps, jazz clubs, comedy stages, rock festivals, rap lyrics, and presidential politics, Four-Letter Nation tells the surprising, rollicking history of America’s forbidden words—and shows that “bad language” has never been merely about bad manners.

The words Americans are not supposed to say have exposed our deepest fights over religion and respectability, class and power, sex and gender, race and rebellion, art and censorship. Again and again, the nation’s censors and reformers—what Jaffe calls the Word Police—have tried to purify American speech, protecting the country from moral ruin one dirty word at a time. And again and again, soldiers, singers, writers, radicals, presidents, and ordinary loudmouths have pushed back.

Funny, erudite, and full of startling stories, Four-Letter Nation is a history of America told through its most forbidden words. It reveals how profanity moved from sin to vulgarity to authenticity, how “low” language became a mark of candor and power, and why our dirtiest language says so much about who we are.