I usually don't pick up New Age /Spirituality books but I was curious about The Power. Parts of it went against my beliefs (Jesus was referred to as the Founder of Christianity). but there were many parts that I found thought provoking along with quotes.
It is not what happens to you, but how you react to it that matters.
The substance of the book is that everything is magnetic and when something good comes to you it magnetically attracts more good things. The same goes for when you give something away. Imagine how you want to be, live like you've already received what you want from life.
Negativity is also magnetic and most of us talk more about what went wrong with our day (weather, work, the government, traffic) than happiness, compounding the negativity.
For as he thinketh in his heart, so is he
Don't let your feelings be reactions. Rather than dwell on negativity, change the way you feel.
Holding on to anger is like grasping a hot coal with the intent of throwing it at someone else, you are the one getting burned.
Success is not the key to happiness. Happiness is the key to success.
Nobel Prize Winner
Rhonda Byrne refers to The Science of Getting Rich by Wallace D. Wattles as her inspiration for her series of books called The Secret. The book by Wallace Wattles is part of public domain and available on The Secret web site (I haven't read it yet)