You can't ask much more from a book than that it changes your life.
Or more correctly, it helps you change your life. I first read this book during my last transition ten years ago, and I'm reading it again for this one. It made all the difference last time, and I'm dipping into the same well a decade later.
Levinson reasoned that while Piaget and Freud had well documented the stages of development of infants and children and adolescents, it mostly stopped at 20. It's as if that's it--you're all grown up now!
He thought perhaps there were changes, phases and stages of adult life akin to those of children. When he researched this with a large number of American males he was surprised to find just how consistent they are.
You can almost set your watch--oops! 25 years old! Time to find a mentor! Ooops 55 years old! Time to be a mentor!
The major transitions he identified at the decade turnovers. They seem to be times of significant discomfort, questioning, reassessment, and redirection in a man's life. They are followed by a period of consolidation and stability--until the next transition ten years later. While the transitions are different for each person and the results are different for each person, each of us in our way goes through them. The "mid-life crisis" he calls the "mid-life transition", since it's only a crisis if you don't get through it well.
This is not a particularly easy read (Gail Sheehey's "Passages" is easier), but if you, or someone you know is trying to figure out "what next?" try this book.
Hey, it worked for me.