Numbers

Q. Why, in many book titles that include ranges of years, is Chicago style for inclusive numbers not followed? As I understand it, Chicago style is to elide the first two digits of the four-digit second number if they are the same as the first two in the first number of the range. The publisher I work for, like many others, follows that rule in general text. But consider, for instance, the subtitle “Self-Portrait of an Actress, 1920–1956.” Do most readers prefer to see titles with ranges of years styled like this one? 

A. You’re correct about Chicago’s style for inclusive dates when a writer chooses to abbreviate them, but CMOS is also fine with spelling them out. In fact, paragraph 9.64 says, “In book titles it is customary but not obligatory to repeat all digits.”

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]