Make a promise to write a credible nonfiction book

A common mistake nonfiction writers make is to underestimate—or worse, ignore—the importance of their subtitle.

You might wonder: Why subtitle? Who cares? Do I even recall the subtitle of my favorite book? Isn't the title alone what's really important?

Well, not exactly.

Yes, your nonfiction book title is crucial because its role is clear: to grab your target readers’ attention and make your book stand out among countless similar titles. (And yes, there are indeed countless similar titles—you need to stand out!)

But here’s the thing: a subtitle has a unique and equally critical role. Its job is to clearly and compellingly promise something specific to your target readers. Think of it like telling your readers:

"In this book, I promise you'll experience a meaningful shift in how you approach ABC," or "You'll finally understand why XYZ works differently than you’ve been told."

Whatever you're writing about, it ultimately comes down to one clear, captivating promise that your audience truly cares about.

But beware: Unmet promises frustrate readers and damage trust. Your subtitle must accurately reflect the essence of what readers will gain by reading your book—no fluff, no hype, no false promises. Just a clear, simple, direct promise in half a sentence or less.

Let me show you what I mean:

Which book engages you more?

When I first saw these different subtitles for the same book by William Dalrymple, I immediately knew which one I'd rather read. The second one promised a clear, compelling narrative—the relentless rise—rather than a vague and overly complex idea.

Brands do this exceptionally well, too. Think of Uber (or Ola). They promise to get you a ride anytime, anywhere, reliably (terms and conditions notwithstanding!). People prefer brands that make clear promises—AND deliver on them.

What are you working on and have you thought of your subtitle? I'd love to know. (This was first published on my LinkedIn page in early 2025).