Parts, chapters, sections, and subsections: how to organize your nonfiction book

30,000-foot view of my writing book

You’ve written (or plan to write) 40,000 to 70,000 words of brilliant prose. Publishers — and readers — will bring a set of expectations regarding structure to the work. Publishers expect you to know how books are organized, but they rarely discuss those conventions explicitly. So let’s break down how nonfiction books are organized.

Chapters and parts: how many, how long?

The first question you’ll face is this: how many chapters, and how long is a chapter? There are two basic approaches here:

  • Lots of small chapters. My book Writing Without Bullshit had 24 chapters, each between 1,000 and 4,000 words. The benefit of short chapters is that people can consume them quickly — for example, reading one or two in twenty minutes before going to bed or listening to them quickly while commuting or exercising. If you’re going to use short chapters, you’ll probably want to divide the book up into parts made up of collections of chapters. My writing book, for example, was divided into four parts on, respectively, justifying my thesis, toxic prose, writing methods, and common formats.
  • Fewer, larger chapters. Many business books have between six and 15 chapters of 3,000 to 10,000 words. This common format typically has a few chapters introducing the thesis, followed by some chapters that follow the structure of your argument (for example, five steps, or four eras), and ending with chapters that extend the thesis or draw final conclusions. Check out Jay Baer’s book Talk Triggers for a great example.

The organization into chapters is central to how you create the book. You should track research and stories by chapters, write fat outlines for them, set deadlines for completing them, and send them to editors, coaches, or coauthors when they reach various stages of completion. (There are authors who work on books in bits and pieces and then sew them together, but I find this method maddening — it’s especially hard on your collaborators who are trying to get a sense of what you’re working on.)

The chapters should be roughly the same length. You can have a 2,500 word chapter and a 7,500 word chapter in the same book. But if you have four 3,000-word chapters and one 16,000 word chapter, your book will appear uneven and lumpy to the reader. Consider splitting the big chapter into pieces.

Keep track of word count as you’re writing. While the words-per-page ratio varies depending on fonts, layout, and page size, in general, you’ll be fitting 250 to 300 words per page. If you’ve drafted a chapter and it’s 9,000 words long, that’s 30 to 36 pages in the final book. If it’s one of 12 chapters that will be similar, you’re on your way to a 100,000 word book that will fill 400 pages, once you’ve added stuff like the notes, index, and table of contents. That’s a huge job to write, edit, and revise — and a chore to read, as well. So take a close look at that 9,000-word chapter and ask yourself if you want to keep going along that path.

One more thing. Don’t do an introduction. Some people read them, some don’t — and that means entering chapter 1, you don’t know where they are. You can put the stuff about what’s next in the book at the end of chapter 1; the rest is self-serving musing that you don’t really need.

Sections, subsections, and head levels

It’s not required to divide your chapters into sections, but it’s easier on the reader to do so. There’s no strict rule about the length of a section — some are just a couple paragraphs, and others are several pages long. Unlike chapters, with sections, it’s fine to have long ones and short ones in the same chapter.

You can also divide sections into subsections.

Publishers talk about head levels. The headings for the first level of sections within a chapter are called “A-heads,” and below that, the subheadings for subsections are called “B-heads.” (They’re also sometimes called H1s and H2s.) The section at the start of the chapter doesn’t need an A-head — it’s introductory material.

So you might have a 5,000-word chapter with five sections. The first section starts with the chapter title, while the other four start with A-heads. One of the sections might have three subsections — there’s an introductory paragraph after the A-head explaining the organization, followed by three three-to-five-paragraph subsections, each beginning with a B-head.

In theory, you can divide subsections further, into sub-subsections starting with C-heads or even smaller sections starting with D-heads. Don’t do this. It’s hard for the people doing the book design to create multiple head levels that are distinguishable from each other. It’s hard for the reader to keep track of the organization if it’s three levels deep. This level of subdivision might be appropriate for a textbook, but it’s not a good idea for a business book.

You can still have structure within a subsection, just don’t use C-heads or D-heads to organize it. Instead, use bullets, numbered lists, or just paragraphs with bolded opening sentences (like the bullets near the start of this post). If you do this, it’s best if the bullets or list entries are limited to one or two paragraphs — it’s hard to keep track of the third or subsequent paragraphs of a single bullet.

If you find yourself writing long bullets, rethink your structure. Maybe those long bullets should be subsections. There’s always an ideal organization with A-heads, B-heads, and lists, you’ll just have to think through how to do it.

Structure is crucial to enabling your reader to navigate your prose. Now you know the tools you can apply to it — and you can talk to editors, coauthors, publishers, and people who lay out pages about what you’re trying to do. Tuck this knowledge away, because you’re going to need it any time you write enough prose to create a book.

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  1. Another golden post, Josh.

    Interesting, some editors or styles require that you’ve got at least two B headings under each A heading. I always called them H1’s and H2’s, but I think that we’re talking about the same thing. I wound up using H4’s on my most recent For Dummies’ books out of necessity. It’s a rigid template. In my other non-fiction books, I never went that granular.

    1. I’ve updated the post to reflect the H1/H2 designation, which is also common.

      The two B-heads under each A-head rule is an affectation, and I consider it optional.

  2. Hey – whatever works. My first novel, now final edit prior to publication I have found that the some, mostly introductory chapters tend to be longer. STill I have storter chapters that describe an action, scene, or setup a following chapter. Any comments and or suggestions?

  3. Hi! Thank you very much for this interesting post which actually leads me to a question related to a book I just finished and, happy to say, fits within your guidelines: 87,000 words, 8 parts, 27 chapters, and about 500 words deviation from the means that look like around 3500 words per chapter. but here is the question: I have numbered the parts from 1 to 8 (duh!) while the chapters’ numbers go from 1 to 27, which means that, say, part 4 begins with chapter 12 and part 6 with chapter 18. I did that because of a lot of cross referencing between the chapters and I thought it would be simpler to say “go to chapter 15” than to “go to part 4, chapter 4”. Do you think it’s OK to do that? Some colleagues say yes, others say no and I could not find anything about that on the web. Thanks in advance!

    1. The way you did it is the traditional way, Stephane. Number the chapters from 1 to 27, don’t restart the numbering over again with each part. Frankly, doing it the other way would seem very strange.

  4. Hey Josh! Great article and I am going to get your book. I am fairly new a writing. I was told by a writing coach that my book’s sections and chapter titles should be 40-60 characters plus spaces. He also said I don’t have a real book if it isn’t at least 400+ pages. Is this true? Thank you.

    1. The 400+ page comment is just dumb. These days, nonfiction books are often 45000 to 75000 words, about 150 to 250 pages. Fiction is different, but there are plenty of good novels at 75000 words, which is no where near 400 pages.

      The section and chapter title data is also wrong. Chapter titles can be a word or two (maybe 20 characters) or they can be longer. Same with section titles.

      Sounds to me like your coach is telling you to follow a bunch of silly rules that are wrong anyway.

  5. Josh, I have a book that contains “9 Steps” and I would prefer the chapter numbers to match the steps.

    There needs to some kind of an introduction, which will contain a bit of history and stories that kind of set the tone.

    Then there will be a part at the end that discusses the future and reflects upon the overall concept.

    Any suggestions?

  6. What do you call the parts of the book that are larger than chapters? The things a book is only divided into 3, 4, 5, or 6 of?