Some book design problems announce themselves immediately.

A cover. Margins that are too tight. A font that looks like it belongs on a birthday invitation instead of in a serious nonfiction book.

But some design problems are quieter. You may not notice them at first. You may simply find yourself getting tired as you read. Your eyes may keep losing their place. The page may feel dense, even though the writing good.

One of the most common muted problems I’m seeing in self-published books right now is leading.

Leading is the space between lines of text. More precisely, in typography, leading refers to the vertical distance from the baseline of one line of type to the baseline of the next. The word is pronounced “ledding,” not “leeding,” because it comes from the days of metal typesetting, when thin strips of lead were inserted between lines of type to add vertical space.

The tools have changed. The principle has not.

A page of text needs breathing room.

When there is not enough space between lines, the words can feel crowded. The reader’s eye has to work harder to move from one line to the next. Dense pages can feel heavier than they need to feel, especially in nonfiction books where the reader is trying to absorb ideas, not just move through a plot.

Good leading does not call attention to itself. Readers rarely say, “What excellent line spacing.” They simply keep reading.

That's the point.

Book design should serve the reader. It should make the reading experience smooth, comfortable, and inviting. The design should not get in the way of the message.

I have read and reviewed several self-published books lately that had strong content and, attractive design. The covers were professional. The chapter openings looked good. The fonts were appropriate. The margins were adequate.

But the leading was too tight.

In some cases, the text appeared to be set at standard single spacing, which is fine for drafting a manuscript but usually not enough for a professionally designed book interior. In book layout, the question is not whether the text is “single-spaced” or “double-spaced.” The question is whether the relationship between the type size, line length, margins, and leading creates a comfortable reading experience.

This is an important distinction.

A manuscript is prepared for editing, review, or submission. A book interior is prepared for reading. Those are not the same thing.

When authors format their own books, they sometimes assume that if the font is large enough, the page will be easy to read. But font size is only one aspect of readability. Line spacing matters too. In fact, a slightly smaller font with more leading can often be easier to read than a larger font with lines packed too closely together.

That may seem counterintuitive, especially if you’re trying to make a book look substantial or easy on the eyes. But bigger type does not automatically mean better readability. If the lines are too close together, the page can feel cramped. The reader’s eye may have trouble tracking from the end of one line to the beginning of the next.

The goal is not simply to make the words large. The goal is to make the page comfortable.

Leading also affects the overall appearance of the book. A page with appropriate spacing looks more polished. It feels more open and intentional. A page with insufficient leading can make even good writing feel amateurish.

That's a hard truth, but it matters.

Readers may not know the vocabulary of typography. They may not know why a page feels difficult to read. But they do notice the experience. They know when a book feels tiring. They know when a page looks crowded. They know when the design makes the book feel less professional than the content deserves.

This is especially important for self-published authors because readers, reviewers, bookstore buyers, event organizers, and media contacts are often making quick judgments. They may not say, “This book has inadequate leading.” But they may say, “This doesn’t look professionally published.”

Interior design is part of the book’s credibility.

That does not mean every self-published book needs a fancy interior. Most nonfiction books do not need elaborate design. In many cases, simple is best. But simple still needs to be done well.

The body text should be readable. The margins should give the page enough white space. Paragraphs should be handled consistently. Chapter openings should be clean. And the leading should allow the reader to move through the text comfortably.

There is no single correct amount of leading for every book. It depends on the typeface, font size, trim size, margin width, line length, and the nature of the book. A dense academic work, a memoir, a devotional, a business book, and a large-print edition will all have different design needs.

But as a general principle, standard single spacing is rarely the best choice for a finished book interior.

A common professional approach is to set the leading somewhat larger than the point size of the type. For example, 11-point type might be set with 14-point leading, or 10.5-point type might be set with 13-point leading. Those are not universal rules, but they illustrate the principle: the space between lines should be intentionally designed, not left at a default setting.

This is where authors need to be careful with templates and word-processing defaults. A template can be useful, but it is not a substitute for judgment. The fact that text fits on the page does not mean it is well designed. The fact that the book has fewer pages does not mean the reader is better served.

Yes, increasing leading can add pages. That can increase printing costs. But cramming text onto fewer pages can cost you in another way: it can make the book harder to read.

That trade-off is worth considering carefully.

A book is not merely a container for words. It is a reading experience. If the content is valuable, the design should help readers stay with it.

Before you approve your final interior, print a few sample pages. Do not judge only on your computer screen. Hold the pages in your hand. Read several paragraphs out loud. Read silently for a few minutes. Notice whether your eyes move easily from line to line. Notice whether the page feels inviting or crowded.

When in doubt, compare your page to several traditionally published books in the same genre. Do not copy another book’s design without understanding the details, but do pay attention to how the pages feel. Look at the type size, the line length, the margins, and the space between the lines. Professionally published books can give you a useful point of comparison.

Better yet, ask someone who was not involved in creating the book to read a few pages and tell you how it feels. Do not ask whether they like the design. Ask whether it is comfortable to read.

That’s the real test.

This is also true if you are working with a hybrid publisher or any publishing services company. Do not assume the interior design is right simply because someone else prepared it. Review the pages carefully. If the leading is too tight, say so and ask for it to be changed. You are the author, and your name is on the book. It’s reasonable to expect a book interior that is not only attractive, but comfortable to read.

Leading may seem like a small detail. But small details are often what separate a homemade-looking book from a professionally produced one.

Your words and ideas matter. So does your reader’s experience.

Give the page room to breathe.