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.
(..) She still alive? - She's gonna bleed out. - What a fucking mess. Yeah. Go... This is Echo Zero-Nine, we have unknowns gathering in the southwest rooftops. Locked gate blocking the stairs. Breacher up. Back it up, back up. Hey, back it up. (..)2012 Zero Dark Thirty