Should I publish book chapters as standalone articles before approaching a publisher? [Humanities - Post Doc Stage] Do you encourage the publication of chapters as articles prior to full book publication, with the aim to improve research profile? Or do you advise publishing a book of previously unpublished work? Or do you suggest publishing some and retaining other research? Please detail any experience of this in your response, with reference to approaching publishers if possible.
Publishers are going to look at your background before agreeing to a publish your work. Things looked at include:


Your citation metrics
Reviewers for your publication proposal
Your CV


Publishing some standalone articles will certainly improve all three, but you'd have less material when it actually comes time to publish a book (because the same material typically cannot be reused). So the question effectively becomes, "can I publish now or do I need a better profile?". Only you can answer that question, unfortunately.

If you don't know the answer either I'd suggest contacting a publisher now, and if they reject your proposals, then publish standalone articles first.