Your story exists, either in draft or as a plot plan, so if you favor using a prologue, now is the time to ask yourself if you need one.

Would a prologue:

   1) Provide extra information to enhance the plot?

   2) Be a teaser – bring forward a later drama?

   3) Introduce significant past events?

   4) Give information from an alternative point of view?

   5) Set the scene – time (past, present, or future) – place (city, village, mountains – there is a wide variation here, but the essential is the country)

Reasons to resist including a prologue:

   1) It comprises an information dump – either of the back story or about a character.

   2) It is a message from the author that, if it is needed, should be a foreword or a preface.

   3) A prologue would “hide” a weak first chapter.

Personally, I have only used a prologue in two of my books.

One of them was to be the first in a series that spanned over forty years of a man’s life, and I wanted to introduce him as a boy of seven. (A tragedy that happened to him then affected his behavior forever.) I used a teaser to let the reader know he or she could expect sizzling, graphic sex scenes. This prologue ran to three short paragraphs printed in italics.

The other is in one of my crime thrillers. A man who would appear often, but only be seen from other people’s points of view  (His victim and the detective chief inspector investigating the case) is given a voice in the prologue so the reader is in no doubt what he wants and how he achieves it. This is a full-length chapter in a normal font that precedes “Four Years Later” where I open chapter one.

“Providing extra information to enhance the plot” should be handled with great care and a prologue only used for this purpose if the facts cannot be presently sufficiently promptly within the novel.

“Setting the scene” in a contemporary novel is better done in chapter one. (How often have you wondered if “London” means London USA, London UK, or one of the other twenty-seven towns and cities?) However, a prologue most definitely has a place in some historical fiction and even more in the sci-fi and fantasy genres. No prologue should leave a reader floundering, trying to make sense of future scientific capabilities the characters regard as normal or failing to take in the main character/s when they are wondering where a portal leads or if they can fly or are visible to humans.

If your prologue is an information dump, scrap it. Rewrite where necessary to convey the facts within the story.

Forewords or prefaces are rarely justified except in non-fiction where the author may need to introduce themselves or inform the reader of relevant qualifications.

Finally, if chapter one is weak, all a prologue is likely to do is mask it temporarily, and no author should risk a book being returned, very likely accompanied by a low rating and a critical “verified purchase” review.