I’ve had aspiring authors ask me how many pages a prologue should be. My answer is simple: zero.
The problem with prologues is they are often info dumps. The writer is using a prologue to explain the rules of his or her world or to provide back story. It’s a technique used by writers newer to the craft and, if done wrong, it will turn readers off instead of pulling them into the story.
The rule I recommend writers follow is this: If the information provided in a prologue is done in a way that gives readers insight into what’s to come AND draws them into the story then keep the prologue. If the information can be woven into the story as it unfolds, cut the prologue. Over ninety percent of books fall into the latter category.
If you’re still not sure if you need a prologue, write it. Then as you write the rest of the book watch for places where you can weave the details from the prologue into the story. Most of the time, this is possible.
There are times when a prologue works. For example, in Wicked Lovely, by Melissa Marr, we meet the winter king and learn how dangerous it is for a human to fall in love with him. The prologue is two pages and grabs the reader.
Gena Showalter includes a note from Alice in her novel, Alice in Zombieland. Her prologue is also two pages and gives the reader a hint of things to come.
Another example of a book with a prologue that works is Fallen, by Lauren Kate. She starts with a prologue "In the Beginning" and through the eyes of one of the characters we are able to get a taste of his world and his pain. This prologue is longer, seven or eight pages, but it works because the information doesn’t read like back story or an info dump. It’s intriguing and gets readers to turn the page.
For those writers who insist a prologue is needed because the back story can’t be woven into the novel or that the reader will never understand the unique rules of the world without one, consider this--the subject of prologues often comes up at conferences. Editors and agents give the same response each time: cut the prologue. If you keep the guidelines above in mind while writing your novel, you will discover if you should keep the prologue or cut it.