So, I know for fiction you have to send a query letter, and that usually a book proposal is reserved for non-fiction books. But I came across some sites that say one needs to be ready to hand over a book proposal too, even for fiction - that there're some agents who require this. Firstly, is that true? Or is a query, synopsis and sample chapters enough? Secondly, if I were to write a book proposal for fiction, how should I write this? Thirdly, how is a book proposal for fiction formatted? I've seen non-fiction proposals but I can't see myself doing a similar breakdown for chapter contents, for example. Any advice is appreciated, thanks!