2.1.1.3 Aditional Uses of Commas

When a phrase or date requires a pair of commas, be sure to include both. Do not open the interruption and then forget to close it.

• Crowley arrived in Cairo on April 1, 1904, shortly before the reception of Liber AL vel Legis.
• The passage is, generally speaking, more often quoted than understood.
• The editor should, for example, distinguish a ritual title from a descriptive label.

No comma is needed around the year when the day comes before the month, or when only the month and year are given.

• Crowley arrived in Cairo on 01 April 1904.
• The revised edition appeared in March 1932.

Following Chicago, do not use commas with Jr., Sr., or roman numerals in ordinary prose.

• Kurt Vonnegut Jr. wrote the The Sirens of Titan.
• Jack Smith III would not require commas around the numeral.

In bibliographies and indexes, however, retain the comma when the surname comes first.

• Vonnegut, Kurt, Jr.

Commas are normally used with abbreviations for religious orders, academic degrees, and similar credentials after personal names.

• The scholar Jane Doe, PhD, presented the lecture.
• The Reverend George Tyrrell, S.J., was frequently controversial.

For more detailed guidance on comma use, consult CMS17, §6.16–55.