Hyphens, En Dashes, Em Dashes

Q. I have an ongoing disagreement with another scholar that I’m hoping you can help resolve. He suggests that the phrase “early modern” requires hyphenation when used as an adjective (ex.: “early-modern literature”). I would instead say “early modern literature”; is there a right answer here?

A. Your colleague has reason on his side—the hyphen would help readers understand that you’re talking about literature from the early modern period (or, sorry: the early-modern period) rather than modern literature that was early in some other sense of the word. But the latter reading is extremely unlikely, and your colleague’s preference is contrary to established usage. The Oxford English Dictionary includes a subentry under “early” (adj. and n.) for “early modern” as a compound adjective, and none of the cited examples, which date back to 1817, include a hyphen. Verdict: you’re right and he’s wrong.