At the online Q&A, the Chicago Manual of Style often hears from writers and editors who are frustrated that they can’t find a rule about something. “I’ve searched everywhere!” they say, like kids looking for their shoes.
Never mind that half the time the answer can be found in a dictionary or online search, or in the CMOS index, table of contents, or Search results. It’s the other half the time I’m talking about here. What do you do when you can’t find a rule?
In my experience, the number 1 reason it’s difficult to find a given rule is that there is no rule. I realize that this concept perverts centuries of American educational practice, but I’m telling you that it’s true: beyond a certain reasonable point, English expression is not legislated. We are free!
“After Mary Smith is first mentioned in a text, should she then be referred to as Mrs. Smith, Ms. Smith, or Smith? I can’t find the rule anywhere.” “Is it Lost Boys of Sudan, lost boys of Sudan, or ‘lost boys’ of Sudan? I’ve searched CMOS but can’t find it.” “CMOS lists ‘Department of History’ and ‘the department,’ but what about ‘the history department’?”
Standard grammar and style rules are not that hard to find. If you are at risk of spending more than a minute or two chasing down a rule, consider this ploy: Use your head and make a decision. Record it in your style sheet. Move on.