BLOG SERIES: NEW IN CMOS-17 “Punctuation Additions”

I have been eagerly anticipating the release of the new 17th edition of The Chicago Manual of Style … and anxious to find out if any changes were made that affect the viability of my Proofreading Secrets of Best-Selling Authors!

Since the new edition officially came out this month, I haven’t had a chance to check every rule yet. But I have studied the page on the CMOS website that highlights the major changes, and I am pleased (and relieved) to report that, as far as I can tell, the PUGS guidelines in Proofreading Secrets remain correct.

There have been a few additions and clarifications, however. So I will be blogging about the ones that I think are of interest to authors and editors, starting this week with some punctuation additions:

6.52: Commas with “too” and “either”

The adverbs too and either used in the sense of “also” need not be preceded by a comma.

  • I had my cake and ate it too.
  • Anders likes Beethoven; his sister does too.
  • The airport lacked charging stations; there were no comfortable chairs either.

When too comes in the middle of the sentence or clause, however, a comma aids comprehension.

  • She, too, decided against the early showing.

 8.185: Titles of folktales, fables, nursery rhymes, and the like

Folktales, fables, fairy tales, nursery rhymes, and the like are usually treated in the manner of shorter poems and set in roman type and enclosed in quotation marks. Italics should be used to refer to fairy tales published as books, plays, and the like. Examples:

  • “Aladdin” is arguably the most well-known tale in A Thousand and One Nights.
  • “Rumpelstiltskin” originally appeared in the Grimm brothers’ Children’s and Household Tales.
  • Everybody knows at least one verse of “Jack and Jill.”
  • Ella Enchanted is a retelling by Gail Carson Levine of “Cinderella.”
  • The opera Hansel and Gretel (Hänsel und Gretel) is based on the fairy tale of the same name.

9.57: Telephone numbers

In the United States and Canada, telephone numbers consist of the prefix 1, an area code, and a seven-digit number consisting of a three-digit exchange prefix followed by a four-digit line number. When written, the seven-digit number is separated by a hyphen. To signal that it may be optional for local calls, the area code is often placed in parentheses. The prefix 1 (not always necessary to place a call) can be omitted. (Its appearance with toll-free numbers is customary but not mandatory.) An extension follows the number, separated by a comma.


  • (123) 555-0000 or (1-800) 123-4567
  • (123) 555-0000, ext. 1234

An alternative style drops the parentheses.

  • 123-555-4567
  • 1-123-555-4567

Either style is acceptable as long as it is used consistently. (The use of periods or other punctuation as separators in place of hyphens is generally not recommended.)

For international numbers, use spaces rather than hyphens as separators. A plus symbol, which stands in for the international prefix, is placed immediately before the country code, with no intervening space. Because their meaning may not be clear, parentheses should not be used for international numbers. Examples:

  • +52 55 1234 5678 (for a number in Mexico City, Mexico)
  • +66 2 123 4567 (for a number in Bangkok, Thailand)
  • +44 20 1234 5678 (for a number in London, UK)
  • not +44 (0) 20 0000 0000

If the international prefix must be expressed, it precedes the country code and is separated from it by a space. A US or Canadian number written for an international audience follows a similar pattern.

  • +1 607 123 4567 (for a number in New York State)

I’ll be sharing more changes from CMOS-16 to CMOS-17 in the coming weeks. But if you’ve found a guideline in the 17th edition that differs from Proofreading Secrets of Best-Selling Authors, please let me know. I’d love to hear about it!