Differences between fiction and non-fiction book proposals
Fiction books are much riskier before a publisher decides to make a bet on them. This is why the proposal has to be in detail. It requires generally the following to be in the proposal.
With non-fiction book proposals the concept can be there along with a couple of chapters, and a proposal can be written out to publishers to consider offering a publishing contract on the project that is currently in the works.
The following should be in the proposal: