The Fourth Turning: An American Prophecy is a book written by William Strauss and Neil Howe that explores the idea of a cyclical pattern in American history and how it might predict future events. The authors argue that American history can be divided into four "turnings," each characterized by a different mood and set of events. According to the authors, the United States is currently in the midst of a "Fourth Turning," which is a time of great crisis and upheaval. The book discusses the potential consequences of this crisis and how it might shape the future of the country.