If you've never been published before, you're an 'unknown quantity', so you're going to have difficulty selling your first novel.
('chiefly US') The 'big unknown' [=the important thing that everyone would like to know] is how investors will react.
A 'fear of the unknown' kept her from changing jobs.
(..) access to use the phone. Hey. Sorry, but you understand, though, given Ava, and you being kind of an unknown. I mean, a great guy. Instant pals, and so on. Who are you gonna call? Oh. I don't know. (..)2014 Ex Machina