Ms. Ford has genuine gems in places throughout the book with lots of tips and suggestions, but I don't see how an individual can tackle everything she proposes in 21 days. The first six chapters set the stage for a practice she suggests. Debbie calls this cleanse a "game." I suppose word usage can help trick the mind.
The first six chapters
Preparing for the Game
Once this groundwork then book is broken into The Past, The Present, The Future over 21 days. So you're applying her ideas to times in your life.
I didn't do the 21 day practice, nor did the opening chapters make me feel compelled to do the work. I underlined some passages but didn't finish the book.