in Editing
When a prologue earns its place
Prologues have a poor reputation, and many deserve it. Some, though, do work the first chapter cannot. Here is how to tell which yours is.
Prologues are one of the most debated devices in fiction. Some readers skip them on principle. Some editors ask for them to be cut by default. Yet many well-loved books open with one, and some would be weaker without it. The question is not whether prologues are allowed but whether a particular prologue is doing necessary work.
What a prologue is for
A prologue is a section that stands apart from the main narrative, usually set at a different time, in a different place or from a different point of view. That separation is its purpose. If the material could simply be chapter one, it probably should be.
Prologues tend to work when they do one of a few specific things. They may show an event that happened long before the main story and shapes it, where placing that event in flashback would be awkward. They may show something the main characters cannot know, creating dramatic irony for the reader. They may establish a frame, such as a narrator looking back, that the rest of the book sits within. Or they may set a tone that the opening chapters, for good reasons, do not.
Why prologues often fail
The most common reason a prologue fails is that it is doing the job of exposition. A few pages of history, mythology or world-building placed before the story begins ask the reader to absorb information before they have any reason to care about it. The reader has to start the book twice: once with the prologue, then again with chapter one.
Another failure is the teaser prologue: a dramatic scene lifted from later in the book, placed at the front to create tension. This can work, but it is often a sign that the actual opening lacks tension on its own. Readers may also feel cheated when the tension resolves differently from how the teaser implied.
A third problem is length. A prologue that runs as long as a chapter, with its own characters and arc, becomes a second opening the reader must invest in, only to have it put aside.
Questions to ask
If you have a prologue, try these. Does the reader need this information before chapter one, or could it come later? Would the book be confusing without it, or just slightly less explained? Is the prologue from a point of view or time that the rest of the book cannot reach? Does it create a question the rest of the book answers?
Then try reading the book without it. If chapter one works as an opening and the prologue's information can be woven in later, the prologue is probably not needed. If chapter one feels unmoored or the book loses a layer, the prologue may be earning its place.
If you keep it
Keep it short. Make it vivid, with a scene rather than a summary. Make sure it raises a question rather than just delivering answers. And make sure chapter one opens strongly in its own right, because some readers will have skipped straight to it.