Thanks for your interest! I'm happy to hear about your book idea. I appreciate requests that are straightforward and give me an idea of what the book is about; if it sounds like it's for me, I'll tell you that, and if it's out of my wheelhouse but sounds like a viable project, I may be able to suggest other ghostwriters. I charge $15,000-30,000 for book proposals and six figures for full manuscripts, depending on factors such as how much research is required, timeline, length, complexity, and so on. I do not work for percentages alone, even if you're absolutely sure it'll be a bestseller.