No place on the globe has been more crowded with utopian longing and utopian experimentation than the United States in the middle of the 19th century. Countless people on both sides of the Atlantic believed that a new and wondrous society was about to take form in the American wilderness. It was a time when the imminence of paradise seemed reasonable to reasonable people.

Between the American Revolution and the Civil War, nearly one hundred utopian colonies were founded in …