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.
(..) B-A-B-Y. Baby. Be on the lookout for a purple Chevy Caprice. The whereabouts of these felons are unknown. Four policemen were wounded in a downtown shootout. Police say not to approach under any circumstances. Still at large, are considered (..)2017 Baby Driver
(..) Always. You got it. Spread to the edges! ...is a young Caucasian male. His identity remains as yet unknown, and police are appealing to anyone who might recognize him to come forward. The search for (..)2017 Baby Driver