I’m planning to send queries to agents about the first book in my new series. I wonder if I should mention that I’ve self-published six books in another series, not the new one. I’m guessing that this would show that I’m passionate and disciplined enough to finish book-length works. And that I will continue to write rather than just turn out one or two books and then quit.
But I'm unsure. Do you think the SP mention would help or hurt my chances of getting an agent?
A QUERY for a finished book would already indicate you finished a book. And there's lots and lots of books out there; showing you can finish a book does lift you above a large percentage, but still leave you with maybe a thousand competitors per given book to make it.....
On the flip side, right or wrong, and fairly or otherwise, going out of your way to trumpet that you have 6 datapoints (you're an engineer, I'm a biologist, let's get nerdy with this--that IS what you'd be showing, 6 datapoints) where you performed at a level far below what they need for a commercial success could suggest some various negative things you may not wish to unintentionally suggest. After all, if you have 6 books and none of them sold over a few hundred copies, someone could conclude you're failing to grow a reader base.
My suggestion would be to omit them. Write a query so good the agent could care less if your prior self-pub books were on how to gut kittens, and a book even better than that. But given the constraints of a query, I wouldn't use ten words to describe prior self-pub experience unless you sold very well. Worst case you needed those ten words to make a better query, and absolute best case you HAE a great query, and concluded with less-than-great statistics at the end instead of closing strong.