Even though the book doesn’t define itself with these words the most important theme is so called out of the box thinking. So how the out of the box thinking works in the practise? The first rule is to forget old approaches, feelings, believings and get a fresh start from an empty table.
You have a problem so you need a solution that solves it easily and quickly. That’s how it works. It’s also important to acknowledge that very often human decisions are based on the illusion that they would know more than they actually do. There’s an example in the book that tells the story of Japanese Takeru Kobayashi who invented a new technique to eat hot dogs. He first dipped the rolls in water instead of trying to swallow them dry. I encourage to read the book you are into creative thinking.