A prologue is a valid literary device—but use it knowing that some readers will skip it. Some claim prologues force them to start books twice. Others have been jaded by prologues that convey backstory that should’ve been worked into official chapters. Others swear prologues set in the future are simply teasers stuck in when Chapter 1 isn’t gripping enough. These real pitfalls give prologues a bad name. Be sure your prologue provides setup that readers truly need and that truly can’t be worked into the chapters. Be sure you’re not teasing a future event because you fear your Chapter 1 starts the story at too quiet a moment. Experiment. Dump your prologue and see if the story is fine without it. If the opening is now too quiet, put the blame where it belongs and rewrite Chapter 1. If you really do need the backstory info, work it into the main story. Don’t dump it all in Chapter 1, though. Tease out the details, if you can. That makes for fun reading.