The agent said yes to the query letter! Finding out how write a book proposal is your next step.The agent will let you know what they want to see. Even with an affirmative response, they don't always ask for a full manuscript. A nonfiction book hasn't been written yet in most cases, so there isn't a manuscript to send. What publishers and agents will ask for is a proposal for your nonfiction book.A Nonfiction Book ProposalConcept:A brief, no more than one page description about why your book is unique.Market:Who will buy your book and why. Include the demographics of your potential readers and how many of them there are. If you can, ...