It's becoming the question I dread, because my answer always elicits a sort-of slack-jawed, glazed-eyed expression. The convo goes something like this:
Friend (enthusiastically): Oh, that's exciting about your book! When's it coming out?
Me: Well, sometime in the next 18 months. I'm not sure exactly yet.
Friend (with slack jaw and glazed eyes): Well, that's, uh, great.
I might or might not try to make excuses about publishing contracts and lawyers and revisions and marketing and covers and God-only-knows-what else because I don't understand all the hoops it has to jump through yet myself.
Usually, I just mutter something incoherent and shuffle back to Fantasy Island (the writing space in my house formerly known as the man cave).