Recently, several people have been asking variations of the same question about agented submissions, so I thought I’d address it here as a frequently asked question.

How do I get my agent in touch with you in regards to submitting a fantasy MG series of mine. Would he send to the slushpile? The reason I ask is that he is currently pitching to editors and I’m very interested in working with Mirrorstone and yourself.

That’s great! I’m always open to new authors, whether agented or not. Agents aren’t submitting to the slush pile per se–it just happens that we prefer mail submissions for logistical reasons, from both authors directly and from agents.
I think I’ve mentioned before that Mirrorstone is a very small imprint. I mean really small. In the editorial department there’s me (the associate editor), the senior editor, and part of the time of an assistant editor. So don’t worry–if something is addressed to me it ends up in my lap and I’ll be able to tell right away that it’s an agent.
You can find details on how we like to receive submissions at our submissions guidelines. The most important thing for an agent to know, of course, is that the address is P.O. Box 707, Renton, WA 98057-0707, sent to my attention.
However, if your agent has more specific questions, he’s welcome to email us at mirrorstone [at] wizards [dot] com. We just prefer not to receive submissions at that address.