If you're checking out this review, you're interested in becoming a better person, or as Kelly says, a better version of yourself. Kudos. This book will help you do it. It has brought a certain clarity to my inner monologue that I have never before felt.
And just so you know, I've read so many self-help books and books on seeking happiness I can't begin to list them here. (Relatively) Recently written books like "The 7 habits" and Dale Carnegie's "How to", all the way to Existentialist writers like Camus and enlightened thinkers such as Thoreau and ancient philosophers such as Aristotle and Plato. Whether or not you have, this book will put all the others into perspective. It will show you how those books, and this one, will help you on your journey of becoming the best version of yourself, and the byproduct (happiness) which comes from embracing this journey.
One last note...I subscribe to no particular faith, and I have avoided reading Kelly despite some of my friends recommendations because his books are always in the Christian section of the book store. I guarantee you that whether you are a born again Christian or an agnostic, this book can help you.
I don't know how else to put it: I give this book my strongest recommendation. You will do well to read it.