What are "interstitials" in writing?

Use this advanced writing technique to strengthen your story's thematic threads

The thing between the things… Photo by Romio on Unsplash

A quick search on the word “interstitial” will return plenty of uses: in medicine, animation, advertising, ecology. But there’s not nearly enough discussion of how interstitials are used in storytelling. I’m here to remedy that for you today!

What is an interstitial in the context of writing?

In general, “interstitial” refers to something that occupies the small spaces between larger parts of a whole. Think of the microscopic organisms that live between grains of sand or those annoying full page ads that pop up when you click between pages of a website… all interstitial!

In writing, I define interstitials as short snippets of a separate storyline that happen between your full chapters. They often show up as a story-within-a-story.

One of my favorite examples of how interstitials can be used is Elana K. Arnold's What Girls Are Made Of*, a YA contemporary novel that has a fairytale-like story woven through in small pieces between chapters.

*This is an affiliate link for Bookshop.org. I may receive a small commission if you choose to purchase the book using this link.

Interstitial or multi POV? How to decide.

Interstitials can be used to great effect to add texture and thematic resonance to your story, but it’s important for you to determine whether your “story-within-a-story” is truly separate from the main storyline or if it is a fully realized point of view.

If I had to sum it up, I would say:

• If you have a large enough story-within-a-story that needs to be told in full chapters – either because it affects your main storyline or follows a character that holds more weight – then it deserves to be treated as another point of view.

• If the story within a story is thematically related is set in a different time period or a different story world (e.g. if your story within a story involves magic while your main storyline is set in our ordinary world), then you’d want to format it as an interstitial.

Some more tips

There are no hard and fast rules here; “interstitial” is a broad term that can encompass a range of creative uses of the space between larger pieces of your story. Here are some helpful tips to consider:

• Ask yourself why you're telling the story this way and what it means to the reader. What does this point of view add to the story that you don't already have?

• The choice to use interstitials is often a stylistic one so try playing around with voice and format. This is a place where you can shake up the writing style without derailing the momentum of your main storyline. For example, you might add in short newspaper articles to give historical context.

• Interstitials don’t have to show up between every chapter. If your story within a story only needs three or four mini-chapters to be effective, that’s fine!

• Don’t use interstitials to just to introduce a character that you have plans for in the second book in a series; there are lots of ways to set that up without pulling the reader into a new point of view.

Words of warning…

I love a good interstitial; I am working on a story right now where I use them. At the beginning of each of my four acts, I’ve added a small chapter of less than 500 words told from a different point of view that doesn't exist in the main story.

That being said, I suspect a lot more people try to write books with interstitials than actually succeed in getting published. I've been told that about my interstitials, but I'm going to hang on to them with a deadly grip because I love it and, for now, I’m willing to make that trade-off.

Do you have any favorite examples you can share?