I admit to having a strong prejudice against prologues in works of fiction. Often they’re evidence of authorial self-indulgence or laziness. Often they’re a piece of Writing (with a capital W) that doesn’t fit in the story but the author can’t bear to leave it out. They constitute an obstacle to getting into the story.
I don’t want a shadow over the rest of the narrative, and I don’t want cutesy hints of what’s to come way before it actually does or I care about anybody involved. I want to find things out when the P.O.V. characters do.
I suppose an example is in order. If you’ve seen the movie and read the book The Fellowship of the Ring, you know that they begin differently. The movie begins with a prologue, which maybe works cinematically, but I am so glad Tolkien didn’t choose to start his novel that way. Instead, he starts out grounded in his story’s here and now, the everyday reality of the hobbits, and only gradually lets us (and them) in on the darker and more epic matters that are afoot.
I like being immersed in the world of the story, not briefly dunked in one world, then pulled out and whisked away to a different one.