Audiobook.
I gave it 5 stars, not because it is a piece of art among self-help books, but simply because of its simplicity. I love how the author connects classic behaviorism in the shape of Pavlov and Skinner's findings into simple human behavior that by repetition and the associated case became habits. I love this summary as validation of my personal findings in basic psychology courses with the addition of some practices and strategies that can be implemented to achieve success.