Q. I edited a travel book for children, and I would love to know your response to this comment from an Amazon reviewer: “U.S. is spelled US throughout the book; D.C. is also spelled without the accurate punctuation. That sort of inattention to accuracy is inexcusable.” The author has asked me to write a response to this for Amazon. This reviewer seems to think Chicago style is teaching kids bad punctuation habits. Thanks for your help.

A. “DC” (no periods) is the official postal abbreviation, in use since October 1963, when the US Post Office Department (now the US Postal Service) introduced its list of two-letter abbreviations for states and territories (and the District of Columbia). The Chicago Manual of Style now recommends these familiar two-letter forms over the traditional abbreviations. So we recommend not only “DC” rather than “D.C.” but also, for example, “IL” rather than “Ill.” Chicago’s preference for “US,” on the other hand, accords with established usage for other countries (the UK, the former USSR, the PRC) and for most other initialisms and acronyms that take full capitals (NASA, UN, DNA). It is true that many publications still favor the more traditional forms with periods, and those are not wrong. But it would be wrong to suggest that kids can’t learn to appreciate the details that make reading (and editing) so interesting.