In the book, Tocqueville examines the democratic revolution that he believed had been occurring over the previous several hundred years. In 1831, Alexis de Tocqueville and Gustave de Beaumont were sent by the French government to study the American prison system. In his later letters Tocqueville indicates that he and Beaumont used their official business as a pretext to study American society instead. They arrived in New York City in May of that year and spent nine months traveling the United States, studying the prisons, and collecting information on American society, including its religious, political, and economic character. The two also briefly visited Canada, spending a few days in the summer of 1831 in what was then Lower Canada (modern-day Quebec) and Upper Canada (modern-day Ontario).