If I had read this book previously before I got into the writing process, I'd have neither valued nor finished the book.
When I'm slow and down in my creative process, I picked up this book and it helped me to start my routine again. All the things Liz mentioned in the book encouraged me to stop the complaining and focus on the work I got to do.
To get motivation through this book would be tough since the author writes with a lot of anecdotes that talks more about the creative process as a spiritual process. If one doesn't buy this idea, then everything Liz talks would be debatable to the reader.