Chicago Manual of Style 17 in 2026: Complete Guide for History, Humanities and Social Sciences

The Chicago Manual of Style (CMOS), 17th edition is the leading citation and editorial standard in history, fine arts, religious studies, business and many humanities and social science fields. Published in September 2017 by the University of Chicago Press, CMOS 17 is still the current edition in 2026 (an 18th edition is expected but has not yet been released as of May 2026). This guide covers everything a thesis writer or graduate student needs to use Chicago 17 correctly.

This is the authoritative practitioner reference, not a marketing summary. All examples are checked against the official Chicago Manual of Style Online (https://www.chicagomanualofstyle.org).

Two Systems: Notes-Bibliography (NB) and Author-Date (AD)

Chicago's defining feature is that it offers two parallel citation systems, each suited to different disciplines. Both are equally official; you pick one and use it consistently.

Notes-Bibliography (NB) is the older, more traditional Chicago system. You insert a superscript number in the text; the corresponding footnote (or endnote) gives the full citation. A bibliography at the end lists all sources alphabetically.

Author-Date (AD) is closer to APA. You cite (Author Year, page) in parentheses; a reference list at the end gives full details. No footnotes for citations (though you can still use footnotes for substantive remarks).

If your discipline is history, art, music, theology, or literature, use NB. If you're in business, social sciences, or sciences using Chicago, use AD. When in doubt, your supervisor or the assigned reading list signals which system is expected. Mixing the two systems in one paper is forbidden.

What Chicago 17 Is, Who Maintains It, and When to Use It

The Chicago Manual of Style is published by the University of Chicago Press and is more than a citation style: it's the leading English-language editorial reference, used by book editors, journal publishers and government style guides worldwide.

Official source: https://www.chicagomanualofstyle.org
Free quick guide: https://www.chicagomanualofstyle.org/help-tools/quick-guide.html
Book: The Chicago Manual of Style, 17th edition (1,144 pages, hardcover or online subscription).

Disciplines using Chicago 17 (NB) as their default:

• History (all subfields)
• Art history, architecture, art studies
• Theology, religious studies, biblical studies
• Musicology, music history, music theory
• Classical studies, ancient history
• Some literature programs (especially comparative literature, world literature)
• Anthropology (some programs)

Disciplines using Chicago 17 (AD) as their default:

• Some business and management programs
• Some social science programs (sociology, anthropology)
• Some sciences (less common; more often IEEE, AMA, Vancouver, or APA)

If you don't know which Chicago system to use, ask your supervisor before writing. Switching mid-thesis is extremely painful.

Turabian: The Thesis Version of Chicago

Kate L. Turabian's A Manual for Writers of Research Papers, Theses, and Dissertations is the student/thesis adaptation of CMOS. It's published by the same press and follows the same rules with simplifications and a focus on student writers.

Current edition: 9th edition, April 2018.

If your university or department specifies "Turabian", use Turabian 9. The rules are 95% identical to CMOS 17. Turabian explicitly addresses thesis formatting (title page, table of contents, abstract, chapter headings) that CMOS leaves to your university handbook.

Many humanities graduate programs use Turabian for dissertations and CMOS for journal submissions. Check which one your program requires.

Notes-Bibliography System (NB): In-Text and Footnotes

In the NB system, every cited source appears in two places: in a footnote (or endnote) and in the bibliography.

Footnote: full citation on first mention

The first time you cite a source, the footnote gives the full citation.

First footnote (book):

1. Jane Smith, The Reading Mind (New York: Routledge, 2023), 142.

First footnote (journal article):

2. Adam Jones, "Memory Consolidation during Sleep," Sleep Research Journal 12, no. 2 (2022): 45-60, doi:10.NNNN/example

The footnote begins with the author's first name first (not surname-first like in the bibliography). Title in italics for books, in quotation marks for articles. Publication details in parentheses. Specific page reference at the end.

Shortened note: after first citation

After the first full citation, subsequent footnotes for the same source use a shortened form: surname, shortened title, page number.

3. Smith, Reading Mind, 89.
4. Jones, "Memory Consolidation," 50.

CMOS 17 no longer uses "Ibid." (deprecated in CMOS 17). Always use the shortened form, even if the previous note cites the same source.

Substantive footnotes

Footnotes can also contain substantive material (an aside, a clarification, a discussion of a contested point) in addition to or instead of citations. This is one of Chicago's strengths over APA: the footnote architecture allows for richer commentary without breaking the text flow.

NB Bibliography: General Rules

The bibliography appears at the end under the heading Bibliography, centered, on a new page.

Universal formatting rules:

• Single-spaced within an entry, double-spaced between entries (Chicago default; many universities prefer double throughout)
• Hanging indent of 0.5"
• Alphabetical order by first author's surname
• Author names: surname first for the first author, then "First Name Last Name" for additional authors
• Up to 3 authors listed in full; 4+ uses first author + "et al." in footnotes but lists all in the bibliography (up to 10; for 11+, list first 7 + et al.)
• URLs included as direct links; DOI preferred when available

Author names

First author: Surname, First Name. Second/subsequent authors: First Name Last Name.

Smith, Jane, and Adam Jones.

URLs and DOIs

DOI is preferred when available. If both DOI and URL are available, use the DOI:

doi:10.NNNN/example

Stable URLs included as direct links. Access dates included only for time-sensitive content.

NB Bibliography: Examples by Source Type

Book (single author)

Smith, Jane. The Reading Mind. New York: Routledge, 2023.

Title in italics, title case. Publisher format: location: publisher, year.

Book (two or three authors)

Smith, Jane, and Adam Jones. The Reading Mind. New York: Routledge, 2023.
Smith, Jane, Adam Jones, and Lisa Brown. The Reading Mind. New York: 
Routledge, 2023.

Book (four or more authors)

In the bibliography: list all authors up to 10 (then first 7 + et al. for 11+).

Smith, Jane, Adam Jones, Lisa Brown, and Michael Davis. The Reading Mind. 
New York: Routledge, 2023.

In a footnote: first author + et al. (even for 4 authors).

1. Smith et al., Reading Mind, 142.

Book chapter (edited volume)

Dupuis, Marc. "Chronic Pain Assessment." In Treatise on Pain, edited by 
Raphael Rey, 3rd ed., 234-256. Paris: Maloine, 2021.

Edited book (citing the whole volume)

Rey, Raphael, ed. Treatise on Pain. 3rd ed. Paris: Maloine, 2021.

Journal article

Smith, Jane, and Adam Jones. "Reading Speed and Aging in Monolingual Adults: 
A Longitudinal Study." Journal of Cognitive Aging 45, no. 3 (2023): 234-251. 
doi:10.NNNN/example.

Article title in quotation marks. Journal title in italics. Volume and issue without "vol." or "no." abbreviations (just numbers).

Thesis or dissertation

Garcia, Maria. "Cognitive Reserve and Bilingualism in Aging." PhD diss., 
University of California, Berkeley, 2022. ProQuest (UMI 28412345).

Webpage

World Health Organization. "Mental Health and Well-Being." March 15, 2024. 
https://www.who.int/health-topics/mental-health.

For continuously updated pages, add an access date:

World Health Organization. "COVID-19 Dashboard." Accessed May 19, 2026. 
https://covid19.who.int/.

Newspaper or magazine article

Goldstein, Dana. "Reading Scores Recover Post-Pandemic." The New York Times, 
April 22, 2024. https://www.example.com.

Archival source (one of Chicago's strengths)

Chicago has well-developed conventions for archival sources, which is one reason historians prefer it.

Smith, Jane. Letter to John Doe. May 15, 1923. Smith Family Papers, Box 3, 
Folder 12, Special Collections, University of Chicago Library.

Government document

U.S. Department of Health and Human Services. The State of Mental Health 
in the United States. Report no. NIH-23-MH-001. Washington, DC: U.S. 
Government Publishing Office, 2023. https://www.example.com.

Film

Nolan, Christopher, dir. Oppenheimer. Universal Pictures, 2023. Streaming 
video, 3:00. https://www.netflix.com/title/example.

AI-generated content (CMOS Q&A, 2023-2024 guidance)

Chicago's official Q&A treats AI-generated content as personal communication (cite in footnote, not in bibliography):

1. ChatGPT, response to prompt "Summarize the themes of Hamlet," OpenAI, March 14, 2024, https://www.example.com.

For frequent AI use in a research project, document the prompts and outputs in an appendix. Disclose AI use per your institution's policy.

Tweet / X post

@CMSCBs. "CMOS 17 is the current edition in 2026; CMOS 18 has been announced 
but not yet released." X, March 5, 2024. https://www.example.com.

Author-Date System (AD): In-Text and Reference List

The Author-Date system uses parenthetical in-text citations and a reference list (like APA, but with slightly different formatting).

In-text citation

(Smith 2023, 142)

Note: no comma between author and year, comma before page number. Page is included for direct quotes; recommended for paraphrases.

If the author is named in the sentence, only the year and page are in parentheses:

Smith argues that reading speed declines with age (2023, 142).

Multiple authors

(Smith and Jones 2023, 142)
(Smith, Jones, and Brown 2023, 142)
(Smith et al. 2023, 142) [for 4+ authors]

Multiple sources

(Smith 2023, 142; Jones and Brown 2022, 89)

Reference list entries

Reference list entries differ from NB bibliography mainly in: date placement (right after author, in parentheses) and slightly different punctuation.

Book (AD):

Smith, Jane. 2023. The Reading Mind. New York: Routledge.

Journal article (AD):

Smith, Jane, and Adam Jones. 2023. "Reading Speed and Aging in Monolingual 
Adults: A Longitudinal Study." Journal of Cognitive Aging 45 (3): 234-251. 
doi:10.NNNN/example.

The format mostly mirrors NB but with the date moved up. The reference list is alphabetical by surname.

Paper Formatting (Manuscript Layout, Turabian Conventions)

Chicago / Turabian formatting rules for thesis writing.

Margins

1 inch on all sides. Some universities require 1.5" on the left for binding.

Font

Times New Roman or Garamond 12pt is conventional. Some universities specify; check your handbook.

Spacing

Double-spaced throughout for the body text. Single-spaced for: block quotes, footnotes, bibliography entries (with blank lines between).

Indentation

First line of every paragraph: indented 0.5". Block quotes (5+ lines of prose): no quotation marks, single-spaced, indented 0.5" from the left margin.

Page numbers

For Turabian, page numbers go at the top right or bottom center, depending on chapter conventions. Title page (page 1) has no visible number. Front matter (table of contents, abstract) uses lowercase Roman numerals (i, ii, iii). Body uses Arabic numerals starting from 1 on the first body page.

Title page (Turabian)

Centered, distributed vertically:

1. Title (typically 1/3 down the page, bold)
2. Subtitle (if any, on a new line)
3. Author name (lower middle)
4. Submission statement (e.g., "A Dissertation Submitted to...")
5. Institution and department
6. City and date

This is for academic theses. Term papers use a simpler title page or a Chicago-style heading.

Chapter headings

Chapter title centered, in bold or in caps, 1/3 down the page. Section headings flush left, bold. Subsection headings flush left, italic. Use consistent levels throughout.

Key Changes: Chicago 17 vs Chicago 16

Chicago 17 introduced moderate changes from CMOS 16 (2010). Key updates:

1. "Ibid." deprecated: use shortened notes instead.
2. DOI preferred over URL when both are available.
3. Singular "they" accepted as a gender-neutral pronoun.
4. Capitalization of "Black" and "White" allowed (and increasingly recommended) for racial identity terms.
5. Updated guidance for digital sources (eBooks, streaming video, social media).
6. Bias-free language expanded but not as extensively as APA 7 or MLA 9.
7. Author-date system clarified with more examples.
8. Newspaper citations simplified (often by section/page rather than by edition).
9. eBook format guidance added (Kindle, iBooks, EPUB).

If you wrote in CMOS 16, the main practical change is to stop using "Ibid." and to default to DOIs over URLs.

Common Mistakes That Cost Points or Cause Re-Formatting

Five mistakes supervisors flag most often in Chicago papers.

Using "Ibid.": deprecated in CMOS 17. Use the shortened form (surname, shortened title, page).

Mixing NB and AD systems: pick one (NB for humanities, AD for sciences) and use it throughout. Mixing footnote-based and parenthetical citations in the same paper is forbidden.

Wrong format for first vs subsequent notes: the first footnote for a source is full; subsequent notes are shortened. Many writers default to short notes throughout (missing the full citation) or full notes throughout (cluttering the apparatus).

Bibliography vs Reference List confusion: NB uses "Bibliography"; AD uses "Reference List". Don't mix the labels.

Forgetting hanging indent: 0.5" hanging indent on bibliography/reference list entries is mandatory. Use your word processor's paragraph dialog, not manual tabs.

Reference Managers and Chicago 17

Most reference managers ship with both Chicago 17 NB and Chicago 17 AD styles:

• Zotero (free, open source): excellent Chicago support with both NB and AD styles
• EndNote (paid, by Clarivate): Chicago 17 NB and AD both available
• Mendeley (free, by Elsevier): Chicago available but historically less reliable for footnote formatting
• Folio Student: applies Chicago 17 NB or AD layout automatically on import for thesis projects

Verify the style version. Older installations may have CMOS 16 set as default. Also confirm whether you need NB ("Chicago Manual of Style 17th edition (note)") or AD ("Chicago Manual of Style 17th edition (author-date)").

Submission Checklist (Chicago 17 Thesis or Paper)

• Decided NB or AD system (consistent throughout)
• Title page conforms to Turabian or university template
• Margins set to 1 inch (or 1.5" left if binding)
• Times New Roman or Garamond 12pt
• Body double-spaced; footnotes and bibliography single-spaced with blank lines
• Page numbers per Turabian convention (Roman for front matter, Arabic for body)
• First footnote for each source = full citation; subsequent = shortened form
• No "Ibid." (use shortened form even for consecutive citations)
• All in-text citations / footnotes match bibliography / reference list
• Bibliography or Reference List on a new page, label centered
• Hanging indent 0.5" on every entry
• Alphabetical order by first author's surname
• DOIs included when available (preferred over URLs)
• Italics for stand-alone works, quotation marks for articles and chapters
• Up to 10 authors listed in bibliography; "et al." in footnotes for 4+ authors
• Singular "they" used appropriately
• Capitalization conventions for racial identity terms applied
• Final proofread by a fresh reader

For full details on every academic standard, see our academic style guides reference. For comparison of APA, MLA, Chicago and Vancouver by discipline, see our doctoral thesis formatting guide. For the dominant social science standard, see our APA 7 complete guide. For literature and humanities, see our MLA 9 complete guide.

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FAQ

Is Chicago 17 still the current edition in 2026?
Yes. CMOS 17 was published in September 2017 and remains the current edition as of May 2026. The 18th edition has been announced by the University of Chicago Press but is not yet published. Editions historically appear every 7-10 years, so CMOS 18 is expected within the next 1-2 years.

Should I use Notes-Bibliography or Author-Date?
Discipline determines this. History, art, music, theology, classics, religious studies, and many humanities use Notes-Bibliography (NB). Some social sciences, business, and Chicago-format sciences use Author-Date (AD). Ask your supervisor at the start of your thesis: switching mid-writing is extremely painful.

What's the difference between Chicago and Turabian?
Chicago (CMOS) is the editorial reference for editors, publishers, and authors. Turabian is the same style adapted for student/thesis writers, with explicit guidance on thesis layout (title page, table of contents, chapter format) that CMOS leaves to publishers and universities. Turabian 9 (2018) is in step with CMOS 17.

Why does Chicago have two systems?
Historically, Chicago accommodated both humanities (which prefer footnote-based citations with substantive notes) and sciences (which prefer in-text parenthetical citations for compactness). Modern CMOS continues this duality so that both communities can use Chicago without changing their citation culture.

Can I still use "Ibid." in CMOS 17?
No. CMOS 17 deprecates "Ibid." in favor of shortened citations (surname, shortened title, page). Even if the previous footnote cites the same source, use a short form, not "Ibid."

How do I cite AI tools like ChatGPT in Chicago 17?
Per the CMOS Q&A, treat AI output as personal communication, cited only in a footnote (not in the bibliography):

1. ChatGPT, response to prompt "Summarize the themes of Hamlet," OpenAI, March 14, 2024, https://www.example.com.

For projects with substantive AI use, document prompts and outputs in an appendix. Disclose AI use per your institution's policy.

How do I cite an archival source?
Chicago has very detailed conventions for archives. The basic pattern:

Smith, Jane. Letter to John Doe. May 15, 1923. Smith Family Papers, Box 3, Folder 12, Special Collections, University of Chicago Library.

Include: creator, type of document, recipient (if a letter), date, collection name, box/folder, repository. This is one of Chicago's strengths over MLA or APA for archival research.

Are footnotes preferred over endnotes in Chicago?
CMOS allows both. Footnotes (at the bottom of each page) are more reader-friendly for citation-heavy work and are the norm in academic books. Endnotes (at the end of the chapter or paper) are sometimes preferred for journals and to keep page layouts clean. Your supervisor or program will indicate which to use.

What if my source has a DOI and a URL?
Use the DOI. CMOS 17 prefers DOIs over URLs because DOIs are stable. Cite as a permalink: doi:10.NNNN/example

Can I include both a Bibliography and a Reference List in the same thesis?
No. NB uses "Bibliography"; AD uses "Reference List". Use only the label that matches your chosen system.

How do I cite the Bible or other religious texts in Chicago?
For modern Bibles, identify the version in the first citation and abbreviate in subsequent notes:

1. The Holy Bible, New Revised Standard Version (Nashville: Thomas Nelson, 1989), Matthew 5:3.
2. NRSV, Luke 12:32.

The Bible and similar canonical texts are not always included in the bibliography (per CMOS); check your supervisor's preference.

Do I need to include access dates for online sources?
Only for time-sensitive content (Wikipedia, dashboards, social media). For stable scholarly URLs and DOIs, no access date is needed.