Chicago Citation Guide, Author-Date and NB, 18E: Chicago Manual of Style, 18th edition

The Chicago Manual of Style (CMOS) offers two ways of citing.

• author-date
• notes and bibliography (NB) -- this is the classic CMOS format and the most commonly used. 

The 18th edition came out in Fall 2024. Notable changes:

• Place of publication is no longer required for book publishers.
• Inclusive page numbers for essays or chapters within books are no longer required in bibliography entries. Use only the page number of the cited material in the note. 
•  Up to six authors are now listed in a bibliography or reference list entry; if more than six, only the first three are listed, followed by “et al.” In a note or in an author-date text citation, up to two authors are now listed; if more than two, only the first is listed, followed by “et al.”
• A month or season can now usually be omitted in citations of journal articles