The Fourth Turning (published in 1998 ... A human life lasts roughly 80 years. Even though humans are living longer on average today, a full life has always been about 80 years.

So says an eerie generational theory known as the Fourth ... a "turning" every 20 years as one generation displaces another, and that this dynamic between the two creates a crisis every 80 years.

During the 1990s, two amateur historians, Neil Howe and the late William Strauss, developed a new theory of American history in two books, Generations: the History of America’s Future (1991 ...