The Chicago Manual of Style (CMOS) is one of the most respected and comprehensive style guides available, widely adopted in the humanities, including history, literature, and the arts. Unlike APA or MLA, Chicago offers two distinct citation systems: Notes-Bibliography (NB) and Author-Date (AD). Understanding which system to use and how to apply it correctly is fundamental for academic integrity and clarity.
This guide will demystify Chicago style, breaking down its core components, providing practical examples, and equipping you with the knowledge to format your papers confidently.
Two Systems: Notes-Bibliography vs. Author-Date
The first crucial step in using Chicago style is identifying which of its two systems your instructor or publisher requires.
Notes-Bibliography (NB) System
The NB system is preferred in the humanities (literature, history, arts). It uses footnotes or endnotes to cite sources within the text and a comprehensive bibliography at the end of the document. This system is particularly useful when sources contain detailed commentary or require extensive discussion in the notes themselves, allowing for richer textual engagement.
Author-Date (AD) System
The AD system is more common in the social sciences, natural sciences, and some humanities fields, especially when a longer list of sources and a more concise in-text citation method are desired. It uses parenthetical citations within the text, similar to APA, and a "Reference List" (not a bibliography) at the end.
Always confirm which system you should use with your professor or editor before you begin writing.
The Notes-Bibliography (NB) System Explained
The NB system relies on numbered notes and a full bibliography.
In-Text Citations (Footnotes/Endnotes)
When you refer to a source, you place a superscript number in your text, corresponding to a numbered note at the bottom of the page (footnote) or at the end of the chapter/paper (endnote).
- First Reference: The first time you cite a source, the note includes full bibliographic information.
Example: "The impact of the printing press was revolutionary.¹" Footnote/Endnote: 1. Elizabeth L. Eisenstein, The Printing Revolution in Early Modern Europe (Cambridge: Cambridge University Press, 1983), 34.
- Subsequent References (Short Form): For subsequent citations of the same source, use a shortened form, typically the author's last name, a shortened title (if the full title is long), and the page number.
Example: "Further research confirmed this finding.²" Footnote/Endnote: 2. Eisenstein, Printing Revolution, 45.
- Multiple Sources in One Note: If you're citing multiple sources for a single point, separate them with semicolons within the same note.
Example: "Several scholars have explored this phenomenon.³" Footnote/Endnote: 3. John Smith, History of Ideas (New York: Random House, 2010), 121; Jane Doe, Cultural Shifts (London: Routledge, 2015), 67-68.
Bibliography
The bibliography provides a complete list of all sources cited in your paper, arranged alphabetically by the author's last name. Unlike notes, bibliography entries use a hanging indent (the first line is flush left, subsequent lines are indented).
Common Bibliography Entry Examples:
- Book (Single Author):
Eisenstein, Elizabeth L. The Printing Revolution in Early Modern Europe. Cambridge: Cambridge University Press, 1983.
- Book (Two or More Authors):
Ward, Geoff, and Patrick Williams. Postmodernism. London: Bloomsbury Academic, 2018.
- Chapter in an Edited Book:
Frankfurt, Harry G. "On Bullshit." In The Importance of What We Care About: Philosophical Essays, 131–49. Cambridge: Cambridge University Press, 1988.
- Journal Article (Print):
Goldstein, Robert Justin. "The Great Star-Spangled Banner Controversy." Journal of American Culture 17, no. 3 (1994): 5-18.
- Journal Article (Online, with DOI):
Voss, Sarah. "The Ethical Implications of Human Cloning." Bioethics 25, no. 4 (2011): 199–205. doi:10.1111/j.1467-8519.2010.01859.x.
- Website:
Perez, Monica. "The Future of AI in Education." EssayMatrix. Last modified May 15, 2023. https://www.essaymatrix.com/blog/ai-education.
- Newspaper Article (Online):
Smith, Jane. "Local Economy Shows Unexpected Growth." The Daily Herald, March 10, 2023. https://www.dailyherald.com/news/local-economy.
The Author-Date (AD) System Explained
The AD system uses parenthetical citations in the text and a "Reference List."
In-Text Citations (Parenthetical)
Cite sources by placing the author's last name, year of publication, and page number (if applicable) in parentheses within or at the end of a sentence.
- Basic Citation:
Example: "(Smith 2010, 45)" Example within text: "As Smith (2010, 45) argues, the theory has significant implications."
- Two Authors:
* Example: "(Ward and Williams 2018, 12)"
- Three or More Authors:
* Example: "(Jones et al. 2022, 78)"
- No Author: Use a shortened title and year.
Example: "(Chicago Manual* 2017, 101)"
- Multiple Sources in One Citation: Separate with semicolons.
* Example: "(Smith 2010, 45; Doe 2015, 67-68)"
Reference List
The reference list, like the bibliography, is an alphabetized list of all sources cited in the paper, using a hanging indent. The key difference from NB bibliography entries is the placement of the publication date immediately after the author's name.
Common Reference List Entry Examples:
- Book (Single Author):
Eisenstein, Elizabeth L. 1983. The Printing Revolution in Early Modern Europe. Cambridge: Cambridge University Press.
- Book (Two or More Authors):
Ward, Geoff, and Patrick Williams. 2018. Postmodernism. London: Bloomsbury Academic.
- Chapter in an Edited Book:
Frankfurt, Harry G. 1988. "On Bullshit." In The Importance of What We Care About: Philosophical Essays, 131–49. Cambridge: Cambridge University Press.
- Journal Article (Print):
Goldstein, Robert Justin. 1994. "The Great Star-Spangled Banner Controversy." Journal of American Culture 17, no. 3: 5-18.
- Journal Article (Online, with DOI):
Voss, Sarah. 2011. "The Ethical Implications of Human Cloning." Bioethics 25, no. 4: 199–205. doi:10.1111/j.1467-8519.2010.01859.x.
- Website:
Perez, Monica. 2023. "The Future of AI in Education." EssayMatrix. Last modified May 15, 2023. https://www.essaymatrix.com/blog/ai-education.
- Newspaper Article (Online):
Smith, Jane. 2023. "Local Economy Shows Unexpected Growth." The Daily Herald, March 10. https://www.dailyherald.com/news/local-economy.
General Chicago Formatting Guidelines
Beyond citations, Chicago style also offers guidelines for the overall presentation of your paper.
Title Page
A Chicago-style paper generally requires a title page.
- The title should be centered roughly one-third of the way down the page, typed in title case (major words capitalized).
- Your name, course name, and date should follow several lines below the title, each centered on its own line.
- No page number appears on the title page itself, but it is counted as page 1.
Page Numbering
- Pages are numbered consecutively starting with the first page of the main text (which would be page 2 if you have a title page).
- Page numbers are typically placed in the upper right-hand corner.
Margins
- Use 1-inch margins on all sides (top, bottom, left, and right).
Font
- Choose a readable font, typically 12-point Times New Roman or a similar serif font. Consistent font choice throughout the document is key.
Spacing
- The main body of the paper should be double-spaced.
- Block quotations (prose quotations of five or more lines, or poetic quotations of two or more lines) are single-spaced and indented 0.5 inches from the left margin. Do not use quotation marks around block quotes.
- Footnotes, endnotes, and bibliography/reference list entries are single-spaced, with an extra line space between individual entries.
Headings
Chicago style offers flexibility for headings, but consistency is paramount. A common hierarchy involves:
- Level 1 Heading: Centered, Bold, Title Case
- Level 2 Heading: Centered, Regular, Title Case
- Level 3 Heading: Flush Left, Bold, Title Case
- Level 4 Heading: Flush Left, Regular, Title Case
- Level 5 Heading: Flush Left, Italic, Title Case, followed by a period. Text begins on the same line.
Always consult your instructor for specific heading requirements.
Key Considerations for Chicago Style
- Consistency is Crucial: Whichever system you use, maintain consistency in formatting throughout your entire document. Deviations can confuse readers and undermine your credibility.
- Specific Editions: For The Chicago Manual of Style, always try to use the most recent edition (currently the 17th edition) as rules can evolve.
- Digital vs. Print Sources: Pay close attention to how you cite digital sources. Include URLs and access dates (or last modified dates) for web pages where the content might change or move. DOIs (Digital Object Identifiers) are preferred for journal articles when available.
- Punctuation: Be meticulous with commas, periods, quotation marks, and parentheses. Their correct placement is vital for accurate citation. For instance, in NB footnotes, commas separate elements, while in bibliography entries, periods often do.
- Understanding the "Why": Chicago style is designed for clarity and scholarly rigor, allowing readers to easily locate your sources and follow your arguments. Appreciating this purpose helps in applying the rules correctly.
While understanding these detailed rules is crucial, ensuring flawless application can be challenging, especially with complex sources or tight deadlines. Platforms like EssayMatrix can assist with professional editing to guarantee your citations and formatting are perfect, allowing you to focus on your content.
Mastering Chicago style demonstrates your commitment to academic excellence and attention to detail. By following these guidelines, you'll produce well-organized, properly cited papers that meet scholarly standards.