In summary: Viktor E. Frankl takes extraordinary psychological insight and applies it to (and beyond) his incredible experiences within several concentration camps.
Are you still allowed to call Holocaust tragedies incredible? The scope and the extremity of the events are hard to believe from the perspective of the widespread peace and prosperity of a different generation and geography, and yet those horrors are also so widely discussed and broadly verified as to be undeniable. Truth is stranger than fiction and more intense, too. The point being: the whole of what happened takes serious work just to imagine. The events are layered and sophisticated and nuanced, but your mind wants to wrap the whole thing up neatly as "nightmare". Period. Nazi's are devils. The holocaust is hell. What then happens when you start to unpack? Turns out there's more there to be learned. So this book isn't another list of horrors. It's more specific in its goal and general in its history.
If your eyes are squinting and suspicions intensifying, don't get me wrong: the above preface isn't some hedge before an apologist argument. Neither I (nor Frankl, obviously) argues the Holocaust wasn't that bad or that Nazi's were good. But maybe the main lesson of the holocaust was less "don't be sadistic and evil" and more "meaning and purpose are the bedrock of existence". Perhaps that's apples and oranges, or perhaps those two points are more linked than we give them credit for.
Anyway, Frankl doesn't dwell on the above. That's just me rambling. Frankl's more concerned with the individual human being. What keeps him going?
Frankl's answer: To find meaning for your life and to follow through with the pursuit of that meaning. It sounds like a platitude in summary and especially coming from my armchair. But coming from Frankl, described through examples from what got people through concentration camp conditions, it's a spoon fed epiphany.
Some random points:
He distinguishes between disease like neurosis and lack of meaning. Being depressed, sad, or afraid as a result of anxiety over spiders is disease like. Feeling those ways because your don't find meaning in your job is normal. The solution is to find that meaning. The attempt to find and fulfill that meaning is what makes us human.
Pleasure and meaning are not the same thing. You can find meaning in suffering. Implicitly, suffering with meaning can be preferable to pleasure without meaning. Think about that in the context of post-automation consumer-driven pop-culture.
We aren't owed anything. Fulfillment isn't a gift offered to you. It is fought and worked for.