Twenge has written other books about generations. This one goes into detail about the differences between six commonly acknowledged generations. The names and dates she uses are:
-(1925-1945)
-Boomers (1945-1964)
-Generation X (1965-1979)
-Millenials (1980-1994)
-Generation Z (aka iGen or Zoomers) (1995-2012)
-Polars or Alphas (2013-present)
The section on Millenials, of which Twenge is one, seemed to go on forever. The book is long but most pages contain a graph and since most people know a person in each of these generations, it is easy to make connections that facilitate easy reading. The author relies on data banks, surveys, and other sources of large quantities of information to form general opinions on various topics to consider. Sometimes she seems to jump to conclusions, or at least draw conclusions on pretty slim evidence, but experience tends to tell the reader that she is on the right track. It is not laid out in a way that is easily conducive to comparing generations. Since I have read this, I find it is easier to accept others' perspectives when they are from a generation other than mine (Boomer here), and I refer to this reading more than I would have thought I would.