The difficulty with trying to create a predictive model of history by looking at historical patterns is the tendency to have data mining bias and confusing coincidence with causality - this book was written in 1995 and now has essentially been off the mark for the Fourth Turning.
I found this book difficult to read and overly pedantic as there were way too many definitions and redefinitions of generations and way too much detail on describing why the facts of history are (or are not) fitting with the model. This could have been 150 pages shorter
TL;DR version => “Hard times make strong men; strong men make good times; good times make weak men; weak men make hard times”