If you are happy already, it help you understand why.
If you're not happy, you'll the tools here to make the changes you need to get to happiness. Not superficial cheerfulness either - real, core-deep contentment.
If you have or work with children, this is one of the best investments you can make - teach them now to adopt these habits and you will change the course of their lives.
The habits of happiness may be instinctual or long ingrained in you, but knowing the hows and whys will allow you to be more intentional and give you the words to share them with the people in your life for whom they're not so automatic.
What I most enjoyed about this book was the way Dr. Cloud aligned scripture with modern scientific research to show how they fit together perfectly and direct us to the same patterns of behavior and thinking. It is such a mind-boggling blessing to know that God laid out exactly what we need to know and do long before we were equipped to "prove it" under our own power.
This is a quick read, but definitely a must.