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.
(..) pink ball right in the middle. - Who's got a cigar? - Didn't know you smoked, sir. I don't. I just want to chew the hell out of it. Uh, "The woman, identity unknown, is believed to be... "the first female candidate for the elite Navy SEALS training program. Her presence could signal a shift (..)1997 G.I. Jane