Punctuation Marks: A Guide for Nonfiction Writers

by Bennett R. Coles

I know – grammar class was like the most boring class in school. And punctuation marks were never an exciting topic. But punctuation will make or break your writing.

Punctuation marks are important to the flow of a sentence. They insert necessary pauses, they provide clarity, they create links and they express emotion. Punctuation marks can also make the same words convey different meanings, depending on how they’re used. This article will talk about why we use punctuation, outline some basic punctuation rules you really should know, and give an overview of some of the most important punctuation marks in nonfiction writing.

Why Do We Use Punctuation?

Punctuation marks bring structure to a sentence. Without them you just have a series of words that can be interpreted in multiple ways unless they’re given the right context. Punctuation is what adds that context, providing meaning and clarity to sentences. Take this example:

“Some people find inspiration in cooking their families and their dogs.”

Compared to…

“Some people find inspiration in cooking, their families, and their dogs.”

Or how about this example:

“A woman without her man is nothing.”

Compared to…

“A woman: without her, man is nothing.”

In both cases we have the exact same words in the exact same order – but dramatically different meanings. I hope you can see why punctuation matters.

Punctuation is essential to effective writing and it uses very consistent rules. Make sure you know the rules well.

What Are Punctuation Rules?

Punctuation marks are each designed to perform specific functions, and they each have clear rules attached to them. While some punctuation marks are sometimes interchangeable, such as the comma or the dash for a subordinate clause like this one, every punctuation mark is meant to be used consistently. Even in the cases where you can choose one of several punctuation techniques – such as using a dash instead of commas to separate a subordinate clause like this one – there is probably one punctuation mark which is better in each specific instance.

Here are some basic punctuation rules:

Commas, these little marks you see before and after this clause, help separate thoughts within a sentence. They can also help out in lists, summaries, and collections.

Semicolons are used for linking two closely-related sentences into one; they’re particularly good when the two related thoughts are of equal importance.

A colon can also link two related sentences, but there’s a twist: when you use a colon, you’re indicating that the second sentence is more important.

Colons can also be used for other purposes: starting lists, adding emphasis, and introducing concluding thoughts.

Parentheses can enclose information (like side comments or clarifications) that may be interesting but don’t affect the main point of the sentence.

Periods indicate that the sentence is complete.

Question marks, like they sound, are placed at the end of any sentence which is a question. Is this always the case?

Yes! Exclamation marks are used to add emphasis to a thought.

What Are the Most Important Punctuation Marks?

While there are many punctuation marks in English, there are about a dozen that are most commonly used in the nonfiction genre.

The Comma, the Semicolon and the Colon

The comma is the primary mark for separating thoughts, ensuring clarity and making what we’ve written easier to understand. The comma is the main tool for structuring thoughts within a single sentence, giving the reader a moment to pause before going on to the next thought.

The semicolon and the colon each connect two related sentences more closely than a period. Both punctuation marks can also be used in lists: the colon to start a list and the semicolon to separate the items in a list.

The Period

The period is the mark that indicates the end of a sentence. It’s used to complete sentences and to mark an abrupt pause or a thought change. It can also be used for a particular kind of emphasis if you really want to drive a point home, but use this technique sparingly. Very. Sparingly.

Dashes and Hyphens

Dashes and hyphens connect things in a sentence. They’re both horizontal lines – like this – but the dash is the longer of the two and is used to connect related ideas or show a dramatic interjection as one idea jumps to a new one. The hyphen is shorter and is most commonly found connecting two words, like ninety-five, to form a single idea.

Dashes give you a way to jump from sentence to sentence in a way that is abrupt but also connected – kind of like the way we speak. This is a specific style, though, and not always acceptable in nonfiction writing.


There are different kinds of brackets, but they all share a similar function: to enclose content you want to highlight in the text. Often this highlighted text isn’t necessary for the main idea of the sentence but it adds something of interest.

Brackets can also allow you as the writer to offer opposing ideas intertwined in the same sentence. For example, you might think that using brackets is poor style (even if the style guides approve) because it clutters the sentence (but adds depth).

Brackets can also be used for noting small details or providing information that otherwise would be left out of your paragraph.

The Apostrophe

Apostrophes are used for contractions and possessives. An example of a contraction is “don’t” versus “do not” – the words have been pushed together into one and the apostrophe indicates the missing letter. Possessives in English are always indicated by the addition of an apostrophe followed by the letter s. So the “bike belonging to the boy” becomes the “boy’s bike”.

Depending on what country you’re in (and what style guide you’re using) if a word already ends in s then you’ll still use the apostrophe to indicate possession but you may or may not add a second s. If the bike belongs to James, for example, in America it would be “James’s bike” but in the United Kingdom it would be “James’ bike”.

Question and Exclamation Marks

These punctuation marks are often used to show a change in tone or indicate an emotional response. The question mark shows uncertainty, like when we ask questions like “What do you think?”

The exclamation mark is most commonly found after words, phrases, and sentences that express strong feelings. It can also be used for emphasis, but be careful employing it outside of dialog or commentary. Exclamation marks are easy to overuse!

Quotation Marks

Finally, quotation marks are used to create a clear separation. They’re most commonly used to indicate speech, capturing all of the spoken words and separating them from the rest of the narrative.

“I love punctuation,” stated the high school student. “It’s useful and fun!”

But quotation marks are also used to create separation within a sentence if you want to highlight a phrase or even cast doubt on it, such as:

We observed the “training” with some concern.

This use of quotation marks is intended to isolate part of a sentence from the rest, usually to create a contrast.

Breaking the Rules of Punctuation

Can we break the rules of punctuation? Yes, but only do so rarely, and only for a good reason. That reason is usually to grab the reader’s attention – upsetting the normal rhythm of a narrative by breaking punctuation rules is the written equivalent of a shout – but even so it has to be done carefully. Most of the time, you can use punctuation as it’s intended and still score dramatic points.


Punctuation marks are an essential part of writing. Without them our words just run together in an endless stream of consciousness, difficult to understand and easy to misinterpret. Every writer needs to master the basic rules of punctuation and use them consistently. Punctuation marks provide a lot of flexibility for the experienced writer, and while breaking the rules may occasionally be required, most of the time the punctuation rules will give you everything you need to write well.

Best wishes!

If you enjoyed this article and are in the process of writing a nonfiction book, be sure to check out my free nonfiction success guide, drawn from years of experience editing books for bestselling authors (including a New York Times bestseller) and ghostwriting for CEOs and politicians. Simply click here to get instant access.


Leave me a comment below if you have any questions or a specific need that I can help you address – I operate an author services firm that specializes in helping entrepreneurs, professionals and business owners who want to publish books as a calling card for prospects, to establish their status as an expert or to generate additional leads for their businesses.

Here are some related posts I highly recommend:

How to Write a Compelling Book in 12 Steps: A Must-Read Guide for Nonfiction Authors

How to Grow Your Business Writing a Nonfiction Book

Bennett R. Coles is an award-winning author of six books published through Harper Collins (New York) and Titan Publishing Group (London). He is also the publisher at Promontory Press, editor for multiple bestselling authors (including a NY Times bestseller), ghostwriter for CEOs and politicians and the founder of Cascadia Author Services, a boutique full-service firm that specializes in premium author services specifically designed for busy professionals. Our end-to-end services include writer coaching, ghostwriting, editing, proofing, cover design, book layout, eBook production, marketing, printing and distribution.

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