I certainly think it would be worth it, as it can help you refine your current business and help you with any new business ideas that you might have. It would also help fill in any gaps you might have. Have a look at her website, she has e-books now which are broken down into specific area. It always pays to keep learning in business and not stagnate. I like the book as it answers many questions related to "how do I start a business" all in the one spot.