I do not know James Ranson personally, but after reading this book I have a strong sense of his approach to book coaching and editing.
He clearly states that this book is intended for 'authopreneurs' (business owners who wish to write a book) and the first half of the book is heavily weighted to them. However, the second half of the book, especially the parts discussing marketing and professional editing, has nuggets of wisdom for just about all authors, no matter what genre they write in. Planning for post-production time and marketing in parallel to your writing are as applicable to fantasy as they are to a business book.
I recommend this book to all authors. Some will get more out of it than others, but all will benefit from the suggestions therein.