Dear Miss Snark,
At what point in the process of acquiring an agent do I mention that I write in more than one genre? In selecting agents to query, I made sure that each one on my list represents both of the genres in which I write. Should I mention in my query that, while I'm seeking representation for book X in genre 1, I'm looking for someone who can also represent a book in genre 2? Or should I leave that kind of subject until later, and if so, how much later?
Query your strongest work. When you start talking to agents who want you, mention that you have works in another genre. The question isn't whether they do it, but if they're good at it, want to work in that genre and have enthusiasm for it. That's one of the ways you can choose between Agent Eclectic and Agent Focus when the time comes.
I'm not a big fan of mentioning "oh I also happen to have a science fiction novel in my back pocket" in a query letter for a novel told in haiku. I much prefer separate query letters wherein you can fully explain the wonders of your SFF novel set on Rabbitania told in the second person.