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.
(..) - ! - Porter, come in! Porter, where the hell are you? - Go ahead, Bountress. - You've got an unknown - approaching from southeast. - Bountress, you're breaking up. Something's coming right at you! - Say again. (..)2002 Shark Attack 3: Megalodon