I’ve heard a lot of negativity about prologues. Overwhelmingly, the advice is not to use one. However in my opinion, there are times when a prologue not only works but is necessary to the story.
The last manuscript I wrote had a prologue. I’d written about a thousand drafts of the first chapter (which my writing group can verify). No matter what I did, though, I just couldn’t get the right balance of information and action. So I decided to write a prologue.
The prologue shows a scene that happened several months before the main part of the book, so it was disconnected enough that I didn’t want to just call it chapter one. But it established a lot of information that I otherwise would have had to include as flash back or backstory later on, which would have slowed down the pacing. Ultimately, it was a move that really worked for that book.
I would say that a flashback is useful any time you want to reveal important information that is slightly disconnected from the main part of the book. In my case, the time line was what was slightly disconnected between the prologue and chapter one. It could also be that your prologue is written from a different point of view than the first chapter, and that’s what disconnects it.
So those are reasons to use a prologue. However, the advice against prologues isn’t out there without reason. I have read a lot of bad prologues where I really wished the author would just get on to chapter one.
The main problem with prologues is that they’re often too vague to be of use to the reader. I think the writer is under the impression that they’re being mysterious when really they’re just being confusing. These type of prologues tend to read as though the author and the reader are sharing a secret, but only the author knows what the secret is, if that makes any sense.
In conclusion, I say use a prologue if it works for story. Just make sure you know why you’re using it and can justify it’s inclusion because it contains something important.