To tell you what this book is about would result in you not having to read it.
You would also completely miss out on Mr. Gladwell's fascinating approach to following the trails of research and approacable, sharply insightful writing.

I can try and explain this book in a series of exclamations as examples of what you will experience while reading:

No kidding?
Duh.
Oh, my.
I never noticed that.
You're kidding?
No, I don't.
No, we don't.
Yes, that does.
I never thought about that.
Dang.
Gasp.
Now I feel silly.
Well, how about that...

If you have read any of Mr. Gladwell's books, you will enjoy this book as well.
If this is your first go at a Malcolm Gladwell book, I will bet you will enjoy it and then promptly seek out his other works.

Don't Blink.
Well, I think you most certainly should Blink.