Through Lines: Your Book’s Special Sauce Part 1 Nonfiction
How many of you remember McDonald’s “special sauce” advertising for the Big Mac? I was around when they first used it in 1974. (After all these years, I wonder if the recipe is still the same. I’m not promoting McDonald’s.)
So what’s special sauce got to do with writing? It’s my way of creating an analogy to this month’s topic: through lines.
The through line for your book (fiction or nonfiction) is its special sauce. In nonfiction, it’s the core idea or promise you make to your reader (and reiterate in every chapter). In fiction, it’s an invisible thread that holds the premise, plot, and character arc together. (I’ll cover fiction through lines in my next post.)
Another way to think of through lines is like GPS. I’m forever taking other roads than what it recommends, and what do I get? Recalculating. (One of these days it’s going to respond with “Forget you. Find your own way.”) Your through line acts like GPS, keeping you on the right route.
Accomplishing This
- State your core idea or promise in one sentence. If you can’t, you don’t have a through line. Determine your through line before you start writing so you’ve got your map. Also, you will clearly state your core idea/promise in your introduction.
Example: This book will help moms deal with the emotional trauma of their child being sexually abused by a family member. - When you finish a chapter, check it against your core idea. Does the chapter expand, illustrate, or deepen your core idea/promise? If your answer is “meh,” then you need to rework your chapter or delete it (ouch! that’s how important it is).
- Tie your chapter endings back to your through line. However, repeating it word-for-word would get tedious, so you want to merely echo it as it relates to the topic of the chapter.
Through Line Examples
Here are 3 examples from my books.
Carried by Grace
Book through line: This book will help moms deal with the emotional trauma of their child being sexually abused by a family member.
Main point of chapter: Managing your anger
Tying it back at the end: Resolving your anger in a healthy manner benefits both you and your family.
Self-editing & Publishing Tips for the Indie Author
Book through line: This book will provide writers with tips for self-editing and independently publishing their books.
Main point of chapter: Showing instead of telling
Tying it back at the end: Showing captures your readers and propels them forward through your story page after page.
Abba’s Promise
Book through line: From our smallest to our biggest need, God has promised to provide.
Main point of chapter: God provides our needs through others.
Tying it back at the end: Life had delivered unspeakable wounds, but the people of Peak Creative department loved me as brothers and sister in Christ are called to love.
Through Line for Memoir
If you’re writing a memoir, which is nonfiction, the through line takes a slightly different shape because it isn’t a how-to or teaching book.
Like nonfiction: It’s still the core idea or promise the book delivers—what the reader walks away with.
Like fiction: It’s usually implied rather than stated, because you’re showing your life experience as a story, not giving bullet-point lessons.
Example: The Glass Castle by Jeannette Walls
Through Line: The resilience of a child growing up in chaos and neglect, and her determination to build a different life.
You might find your through line changing as you write, so be flexible. Just make sure you go back and review each chapter to ensure it meets your new through line.
Admittedly, I have not used this tool with previous books I’ve written. I’ve carried the through line in my head without realizing what it was and how it guided me through my writing. But as I learn and grow as I writer, I use what I learn to make my writing easier, quicker, and more impactful.
Are through lines new to you? Are you able to define the through line of your current nonfiction work? Now’s as good a time as any to start. Leave the through line to your nonfiction WIP in the comments.
P.S. Want to publish your book in 2026 but not sure where to start? From Dream to Debut will show you the way.
The next cohort of my coaching program From Dream to Debut is launching in February 2026. You’ll learn how to…
- Plan and edit your book with purpose
- Share your message without fear of “self-promotion”
- Establish your platform for long-term impact
To learn more, visit here.