I'm conscious this board might be for critique of blurbs, but the other posts about how to write them got really useful responses and I have a different question. I've 'pantsed' an 80,000 word novel; written its logline and synopsis after the first draft; gone back to edit everything to better fit the synopsis; and then written a blurb for the second draft. The logline didn't mention the main character - it occurred to me that that's probably not desirable, but that it's less important than whether or not the novel can be reduced to a logline. I've tried to do something similar to T F Powys' Unclay (1931) with a new POV character in every chapter. Should I re-frame the logline around the MC? The synopsis wouldn't reduce down to a reasonable length, so I wrote the synopsis I wished for, and then went through cutting out characters and scenes from the first draft to match it. The blurb I know is coming from another direction: why would someone want to read this book. I've made it centre on the MC but I feel there is a tension between what will appeal to readers at first glance, and what they'll most enjoy when they get into it. My question is which normally has to move: the blurb or the novel? Or is it fine to leave a gap between them?
Personally, my view is that the book comes first. The purpose of the blurb, as you have expressed it, is to tell people why they might want to read the book. I don't know what you mean by a gap between them but if you don't think the blurb works for the book, then IMHO it's the blurb that needs to change. As for the logline: https://www.writersdigest.com/formatting/what-is-a-logline
For a novel, should the logline (of the synopsis) always have a central irony? e.g. the writersdigest page gives The Wonderful Wizard of Oz as an example:- "After a twister transports a lonely Kansas farm girl to a magical land, she sets out on a dangerous journey to find a wizard with the power to send her home." But the structure Baum uses could also be loglined to a different or secondary logic-of-composition:- "Dorothy follows the straight and narrow path to a hidden factote, but straightly she unhides him as a narrow facnil." For TWWoO, the emotive logline for a blurb and a structuralist one for a synopsis do match each other closely - but it's a great novel. The structure directly satisfies what the audience approach it for. I've moved the blurb first as you've said - and it's highlighting things in the book to trim out or emphasize. Mostly small things - hopefully that means it's nearing completion.