Chicago style has two different systems of source citation: author-date and notes and bibliography.

Author-Date

The author-date system is used in the sciences and social sciences. In it, sources are cited in-text with a brief parenthetical citation that includes the author’s last name and date of publication along with the page number referenced. Each in-text citation corresponds to a complete source citation in a reference list provided at the end of the paper.

Example:

(Sandel 2009, 39)

Sandel, Michael. 2009. Justice: What’s the Right Thing to Do. New York: Farrar, Straus and Giroux.

Notes and Bibliography

The notes and bibliography system is common in humanities disciplines such as literature, history, and the arts. In notes and bibliography, sources are cited in-text with a numbered footnote or endnote. A superscripted number indicates the citation and a corresponding note includes source details. In addition to the footnote or endnote, a bibliography with a complete source citation is usually included at the end of the paper.

Example:

¹Michael Sandel, Justice: What’s the Right Thing to Do (New York: Farrar, Straus and Giroux, 2009), 39.

Sandel, Michael. Justice: What’s the Right Thing to Do. New York: Farrar, Straus and Giroux, 2009.

This module focuses on formatting citations in the notes and bibliography system. For information about the author-date system, see the Chicago Manual of Style.