The book is based on a 3-part premise. 1. Everybody wants to be happy 2. People are much less happy than they could be 3. People could be much happier if they knew what happiness is and how to get there.
So the book provides, as far as we know for the first time, not only the universal (for everyone) absolute (for all time) definition of what happiness and unhappiness is but most significantly it describes how you, me and anyone can endeavor our way to BE happy in great degree and frequency.
Two significant breakthroughs have paved the way for us to know what happiness is and how we can be happy. One is the the realization that happiness is an experiential "be thing" and can only be understood and described by first understanding the "Be Level of Life" where "Be Things" such as happiness and unhappiness, our self worth whether positive or negative, meaning or the lack of it and more are determined. We'll just say that Happiness is a Be Thing cracks the code on the Be Level of Life and how all of these "be things" are determined.
The other breakthrough has to do with the explanation of the role of the human spirit, our spiritual or higher nature. It turns out that our higher nature is the source of true, enduring, here and now happiness. There is much to that and the associated learnings can be life-enhancing to a great degree.
In summary the book provides anyone with what we can know and understand and do to eventually BE happy. A tremendous breakthrough and catalyst to humankind's inevitable evolution towards our higher nature as self and all the here and now happiness that goes with that.