[joshlemer]

IANAL but my understanding is that public domain material can be published in a copyright protected form, yes. For instance, Beethoven's 5th symphony is in the public domain, but if a publisher starts selling the sheet music for it, then that content itself is still protected. So any contributions they've made such as annotations or formatting, cover art, etc are protected but the underlying content is not.

[JKCalhoun]

Yeah, I understand that Dover books might have a copyright on, say, Moby Dick but it's on the forward that they tackled on to Melville's prose, not the story.