Do you mention other MS in Query??

It would depend on what genres the agent represented I suppose. If you had a childrens manuscript and they only repped adult I would keep that one out. I wouldn't go into great detail about any of that. Agents tend to frown on that in my experience. If the other books are related then it would make the most sense to only mention the ones related to the project you are pitching.

Good luck and God bless! =)

Just say you have other completed manuscripts. Do not go into detail. My agent did not want to know what I was working on until she offered representation and then we discussed it in detail.

I'm going to say no, that you should not mention that you have multiple completed manuscripts. The agent is going to assume that these have not sold because they are bad. Even if it is not true, you don't want to put that thought into the air.

IMO, mention the book you are querying (and only it). Confessions about other manuscripts can come when you are discussing representation.

I think it's a balancing act and that you should tip towards not mentioning. First, if you say you have a lot of completed manuscripts, you're sending the signal that you're not writing publishable stuff (I think Kristin Nelson had a post on this a while back with an author who said in the query that the book was her 10th completed manuscript). Whether you do submit those books or not, the agent will usually assume that you've been submitting everything and thus what you've written before wasn't great. Second, I wouldn't mention a lot of other genres of books because it looks like you're hopping around a lot, not focused on one genre.

I've also read on several agent blogs that while you are ultimately selling yourself as a writer, first and foremost you're selling a book. They're not going to take on a book that they don't like or think will sell because they like you. If they love the book, think they can sell it, and want to represent you, they'll usually offer to represent you no matter how many manuscripts you have under the bed in whatever genres.

ETA: I said in my query that the book was my third completed manuscript.

From the research that I have done, agents want to be queried about one manuscript at a time. They also want to know your "publishing history," not your writing history. If your other manuscripts are not published, don't mention them. The manuscript has to stand on its own.

The agent isn't going to look more favorably on a manuscript because you have written other stuff that hasn't been published. Anybody can write additional manuscripts in other genres without getting them published. It doesn't mean that those manuscripts are any good.

An agent will not look at your manuscript and, when making the decision to represent you, take into consideration whether or not you have written other stuff that hasn't been published.

Queries are supposed to be as short and succinct as possible. Telling the agent that you have additional manuscripts in other genres that aren't published will clutter up the query letter.

The agent cares mainly about one thing: Is the manuscript something that he/she can sell to a publisher?

I've answered this one before, but I'll say it again here: Pick your best book that appeals to the widest possible market and query agents about that one. Find an agent, sell the book, limit the option clause to next in series or next in genre, and then start discussions with your agent about the other books and whether or not they can be shopped if they don't fall under the option clause.

Z