How to Cite Sources in a Nonfiction Book

To cite sources in a nonfiction book, pick one notes system and use it throughout. For most trade nonfiction that means endnotes in Chicago notes-bibliography style, either numbered or keyed to a page number and a short phrase, with a bibliography or a shorter further reading list after them.

Cite direct quotations, statistics, contested or surprising claims, and ideas you took from someone else. Leave widely known facts alone. Record each source the moment you use it while drafting, so the notes section is assembled from a log rather than rebuilt from memory at the end.

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Key takeaways

• Trade nonfiction has four common options: footnotes, numbered endnotes, notes keyed to text with no superscripts, and a bibliography or further reading list on its own.
• Chicago notes-bibliography is the usual default for book publishing in history, the humanities and general nonfiction. Follow your publisher's house style if it differs.
• Cite quotes, numbers, contested claims and borrowed ideas. When you are unsure, cite.
• A citation is not permission. Long quotations, song lyrics, images and unpublished letters may need the rights holder's consent as well.
• In an ebook, every notes system becomes tappable links, so the print choice matters less than consistency.
• Log the source, the claim and the exact passage while you draft. That is what saves the last month of the project.

What are your options for citing sources in a nonfiction book?

There are four, and most books use one main system plus a bibliography.

Dave Chesson on Kindlepreneur (dated 29 November 2023) states the basic split: "Footnotes are found at the bottom of each page, whereas endnotes are found at the end of each chapter or book". The third option is less well known. Jason Pearce, in Footnotes, Endnotes, or Bibliography Only: Which Fits Your Book? on ebookpbook (dated 3 August 2026, modified 21 October 2026), describes it: "The notes section at the back keys each note to a page number and a short quoted phrase." He adds that "Chicago’s editors recognize this style, sometimes called notes keyed to text, and recommend it for general-readership books".

Pearce's rule of thumb for the first two rows is a good one: "if the average reader should read the note, make it a footnote;" notes kept mainly for the record belong at the back.

Which citation style do trade publishers usually expect?

Chicago, in its notes-bibliography form. The Purdue OWL overview of the Chicago Manual of Style (no date shown; read on 1 November 2026) describes "the Notes-Bibliography System (NB), which is used by those working in literature, history, and the arts." Its other system, author-date, "is preferred by those working in the social sciences."

The Author Learning Center page on citation best practices (no date shown; read on 1 November 2026) calls Chicago notes and bibliography "Preferred in book publishing for historical books, literature, and the arts."

In practice:

• Traditional or academic publisher: ask for the house style sheet before you format a single note.
• Self-publishing a general-audience book: Chicago notes-bibliography is a safe default.
• Data-heavy science or business: author-date, with "(Surname, Year)" in the text and a reference list, can feel more natural.

Kaelyn Barron at TCK Publishing (dated 29 September 2020 in the page metadata) notes that "endnotes are best for providing citations and information about sources." Her example uses Chicago, and she reminds authors they "still need to include a complete bibliography after your endnotes page."

What actually needs a citation, and what counts as common knowledge?

Anything a reader might want to check, and anything that is not yours.

The Author Learning Center puts the base rule simply: "Cite the reference whenever text from another source appears in your book." It extends it to facts: "When mentioning a fact that's hard for readers to verify, it's helpful to cite where you obtained the information."

The Purdue OWL page on common knowledge (no date shown; read on 1 November 2026) gives a working test: "Generally, common knowledge is information that someone finds documented in at least five credible sources." Its fallback is the one to remember on deadline: "Remember the golden rule: When in doubt, just cite."

Is citing a source the same as getting permission to use it?

No. A citation tells readers where something came from. Permission is the rights holder agreeing that you may reproduce it. A long quotation can be fully cited and still need permission.

The Author Learning Center warns that credit alone may not be enough and that you "may need to obtain permission from the copyright holder." One of its examples is "Unpublished material, such as e-mails, text messages, or letters of any length."

Fair use is the legal doctrine that sometimes allows use without permission. Authors Alliance (dated 8 September 2017, modified 9 April 2025) explains that "unlicensed use may be legally permitted by virtue of the 'fair use' doctrine," and publishes a guide described as "a guide that helps nonfiction authors make confident fair use decisions."

This is a legal question, and this guide is not legal advice. Ask your publisher about their permissions process, or a lawyer if you are self-publishing and quoting heavily. Keep a separate permissions list from day one: what you quoted, how much, who owns it, and whether you have written consent.

How do notes work in an ebook?

Every system ends up as links. Chesson writes that "for ebooks, your footnotes will be converted to endnotes, since footnotes only work in print." Pearce explains why: a reflowable ebook "has no fixed pages, so there is no page bottom for a footnote to sit on." He describes the result: "Every notes system becomes some form of linked note in the ebook edition: tap the cue, read the note, tap back."

Notes keyed to page numbers need a different cue in the ebook, usually a link from the phrase itself. For heavily noted books, Chesson suggests: "If you intend to have many endnotes, then you should place them at the end of each chapter." In an ebook that keeps the jump short.

The choice is also reversible: Pearce notes it "is not a one-way door while the book is in Word." A manuscript with no record of its sources is much harder to fix.

How do you keep track of sources while writing a book?

Log at the moment of use, not at the end. The Author Learning Center makes the case: "you can stay organized and avoid the headache of tracking down sources after you've written your manuscript."

A workflow that holds up over a long draft:

1. One source list for the whole book. Every book, article, interview and dataset gets one entry: author, title, publisher, year, URL if any, and the type of source.
2. Record the claim, not just the source. Write down the sentence in your manuscript that the source supports. "Kolbert 2014" alone does not tell you, six months later, which paragraph it was for.
3. Save the exact passage. Copy the quote or the paragraph you paraphrased, with a page or location reference in your notes. This is what lets a fact-checker, or you, confirm the claim without reopening the book.
4. Mark the spot in the draft. A bracketed tag, a comment or an inline highlight. Anything you can search for later.
5. Flag permissions separately. Any quotation over a sentence or two, any lyric, image or unpublished letter goes on the permissions list as well as the source list.
6. Choose the notes system at the end. If steps 1 to 4 are done, turning the log into footnotes, numbered endnotes or keyed notes is formatting, not research.

For more on organising the research side of a nonfiction project, see our guide to the best app for non-fiction writers.

What does this look like for one chapter?

A hypothetical example, invented for this guide. Chapter 4 of a popular history of lighthouse keepers runs to 6,200 words and makes 14 claims a careful reader might ask about.

The 10 notes draw on 7 distinct sources: 3 of them are cited twice and 4 once, which makes 10. Two of the four letter quotations are unpublished family papers, so they also go on the permissions list.

The author chooses notes keyed to text, because the book is narrative and superscripts would interrupt the logs. A keyed note at the back reads: "page 87, 'the light failed twice that winter': Harbour Board minutes, 1911." The ebook links from that phrase. The bibliography lists all 7 sources in Chicago style.

Because every claim was logged while drafting, the notes are formatting work, not research.

Where StoryWith AI fits

StoryWith AI has a Sources page for non-fiction books. It appears in the sidebar only when a book is set as non-fiction. Adding sources, citing them and exporting a bibliography use no AI actions.

What it does:

• Add sources with a title, authors, publisher, year, an optional URL, notes and a type: book, article, journal, website, interview, dataset, document or other.
• Cite a source in a scene from the Sources page: pick the scene, write the claim the source supports, and add an optional excerpt (a quote or paraphrase). In the Write editor you can also highlight a passage and choose Cite to attach a source to that exact text; those references appear in the scene's References panel.
• Export a bibliography of the book's sources in APA, MLA or Chicago, either copied to the clipboard or downloaded as a .txt file.
• Carry citations into manuscript exports. For a non-fiction book, the Markdown, plain text, PDF and DOCX exports add an author and year marker such as "(Kolbert, 2014)" after each passage cited inline in the editor, and a References section listing the cited sources in APA format. Our guide to exporting a manuscript to DOCX covers that export.

There is also a fact-check on the Diagnostics page for non-fiction books. It asks the AI whether each citation's saved excerpt supports the claim it is attached to, and marks each one supported, mismatch, unverifiable or skipped. It reads only what you saved; it does not look anything up on the web, so a citation with no excerpt comes back unverifiable. Each run checks up to 30 citations and uses one AI text action from your plan's allowance. "Argument soundness + fact-check (non-fiction)" is listed under the Author plan on storywith.ai/pricing on 1 November 2026; plan allowances are on the pricing page.

When it is the wrong tool:

• It does not create footnotes or endnotes. Exports use an author and year style marker plus a References list, always formatted as APA in the export, whatever style you picked on the Sources page. If your publisher wants numbered Chicago notes or keyed notes, you will set those in Word or your formatting software.
• Its bibliography formatting is simple. Entries are built from author, year, title, publisher and URL. Edition, journal volume, page ranges and access dates are not separate fields, so check entries against your publisher's style sheet.
• It does not handle permissions. Keep your own permissions log.

StoryWith AI runs on the web and on Android; there is no iOS app. Manuscripts are not used to train AI models.

Frequently Asked Questions (FAQ)

Should a nonfiction book use footnotes or endnotes?

Most trade nonfiction uses endnotes, either numbered or keyed to a page and phrase, because they keep the reading page clean. Footnotes suit notes most readers should actually read, such as short explanatory asides. Pick one system and use it for the whole book.

What citation style should I use for a trade nonfiction book?

Chicago notes-bibliography is the usual default in book publishing, especially for history, the humanities and general nonfiction. Data-heavy books in the sciences or social sciences sometimes use Chicago author-date instead. A traditional publisher's house style overrides both.

Do I need a bibliography if I already have endnotes?

Usually yes for research-heavy books, because a bibliography lets readers see every source in one alphabetical list. Lighter books sometimes replace it with a short further reading list. Ask your publisher, or follow comparable books in your category.

What does not need a citation in a nonfiction book?

Widely known facts, your own opinions and your own analysis. If a reader could reasonably ask "says who?", cite it.

Is citing a quote enough, or do I need permission?

A citation credits the source; it does not grant the right to reproduce the material. Long quotations, lyrics, images and unpublished letters or emails may need the rights holder's permission. Fair use is a legal question, so check with your publisher or a lawyer.

How do footnotes work in an ebook?

Reflowable ebooks have no fixed pages, so footnotes become linked notes the reader taps to open and taps again to return. Numbered endnotes and keyed notes become links too. Placing notes at the end of each chapter keeps the jumps short.