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.
(..) - I found him. REPORTER : ...heroically saving an Academic Decathlon team from Queens. The identity of the masked hero is still unknown. - Mom. WOMAN: Oh, kids. All right. Peter. Come here, come here, come here. This past weekend, (..)2017 Spider-Man: Homecoming
(..) Can you summon an army of spiders? No, Ned. The Sokovia Accords were put into place... How far can you shoot your webs? It's unknown. Shut up. --to begin regulating... If I was you, I would stand on a building... - ...and just shoot it as far as I could... - Shut up, Ned. (..)2017 Spider-Man: Homecoming