by Christine Bode
Editors rely on The Chicago Manual of Style, so authors don’t have to. One of the primary roles of a professional editor is to apply CMOS consistently behind the scenes, allowing authors to focus on storytelling rather than technical rules.
If you’re writing fiction or nonfiction for the North American market, CMOS remains the gold standard. It ensures clarity, consistency, and professional credibility. Whether you’re self-publishing a debut novel or preparing a memoir for traditional submission, style matters. Readers notice. Agents notice. Editors absolutely notice.
Consistency in grammar and punctuation doesn’t restrict creativity. Instead, it supports your voice by removing distractions. That’s precisely why CMOS still leads the publishing world. Without further ado, this is The Chicago Manual of Style explained.
Why The Chicago Manual of Style Still Leads
From an editor’s perspective, CMOS works because it balances authority with flexibility.
First, it’s comprehensive. The guide covers nearly every editorial situation imaginable, from dialogue formatting to hyphenation rules. When questions arise, CMOS provides reliable answers.
Second, it respects creative voice. Chicago offers guidance rather than rigid laws. As a result, your writing stays expressive while remaining professional.
Third, it’s the industry standard. Most North American publishers expect manuscripts to follow CMOS conventions. Even for self-publishing authors, this alignment signals seriousness and care.
Finally, CMOS is searchable and accessible. With The Chicago Manual of Style Online, answers are readily available—although working with an editor saves you that time.
The Chicago Manual of Style Explained: Rules Every Writer Should Know
You don’t have to memorize the 1,000+ pages of CMOS, but knowing the following twenty rules will instantly elevate your manuscript. These are some of the most common corrections I make when editing fiction and nonfiction alike:
1. Use the Oxford (Serial) Comma
Always include a comma before the final “and” in a list: red, white, and blue.
2. Use Em Dashes for Emphasis
Em dashes—without spaces—indicate interruptions, emphasis, or parenthetical phrases.
3. Use En Dashes for Ranges
Use en dashes for ranges like 10–20 pages or compound phrases. Note: When editing for British spelling and grammar, en dashes are used instead of em dashes.
4. Place Periods and Commas Inside Quotation Marks
“He said, ‘Let’s write it properly.’”
5. Use Double Quotation Marks for Dialogue
Reserve single quotation marks for quotes within quotes.
6. Italicize Titles of Long Works
Italicize books, films, and magazines. Use quotation marks for short works.
7. Spell Out Numbers One Through One Hundred
Use numerals for 101 and above, except in technical contexts.
8. Use Singular Possessives—even with S
Write James’s book, not James’ book.
9. Format Ellipses with Spaces
Style ellipses as three spaced periods: She paused … then continued.
10. Hyphenate Compound Modifiers Before Nouns
A well-known author; the author is well known.
11. Know When to Use That vs. Which
Use that for essential clauses. Use which for non-essential clauses, with commas.
12. Treat Collective Nouns as Singular
The team wins its game.
13. Use Who and Whom Correctly
Who acts. Whom receives the action.
14. Capitalize Major Words in Titles
Capitalize nouns, verbs, adjectives, adverbs, and pronouns. Articles and conjunctions do not (unless they’re the first or last word).
15. Indent Paragraphs in Fiction and Memoir
Each new paragraph and speaker requires indentation.
16. Start a New Paragraph for Each Speaker
This keeps dialogue clear and readable.
17. Use Commas After Introductory Elements
After all, clarity improves comprehension.
18. Avoid Comma Splices
Don’t link two complete sentences with a comma alone. Use a semicolon, a conjunction, or split into separate sentences.
19. Do Not Capitalize Seasons
Unless part of a proper noun (like Fall Semester 2025), keep seasons lowercase.
20. Use One Space After Periods
Modern publishing standards require a single space between sentences.
Why Style Matters More Than You Think
You might wonder: Does this level of detail really matter?
Absolutely. As an editor, I often say that consistent punctuation and formatting are invisible until they’re wrong. A professional presentation removes distractions and keeps readers engaged in your story. And for agents, editors, and reviewers, consistency signals professionalism, care, and respect for the reader.
When I’m line editing or copyediting a manuscript, applying CMOS standards isn’t about stifling your voice—it’s about clearing the path so your voice flows freely and confidently.
Ready to Polish Your Manuscript?
If you’re feeling overwhelmed by style rules (you’re not alone!), that’s where a professional editor steps in. Whether you’re writing a spellbinding fantasy novel, a heartfelt memoir, or a thought-provoking nonfiction book, I’ll ensure your manuscript not only tells your story but does so with professional polish.
When you’re ready, let’s collaborate. We’ll make your writing the best it can be, while keeping your unique voice at the heart of every sentence.
In the meantime, if you would like a quick reference CMOS cheat sheet, email me, and I will send you one.