This is one of the most important books ever written, in my opinion.
When I want to give someone I care about a meaningful gift, I buy another copy of this book.
I believe it's relevant to everyone, because after all, we're all alive, aren't we? The meaning and significance of life is pretty fundamental to everyone.
I recommend this book more highly than probably anything else I've read. It is fascinating to read about a concentration camp experience through the eyes of a psychotherapist, and his explanation of logotherapy in the rest of the book is fascinating.
The most important concept I took from the book is that it's alright to be unhappy. Now, whenever I'm unhappy I just ask myself, "So what?" and that changes the entire perspective. I'm able to move forward and usually I'm not even unhappy anymore.