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.
(..) Oh, goddamn it! It was stupid. I made a stupid mistake. Forget about it. There are hundreds of unknown subjects out there. I-I can get this guy, Sean. The worst thing a paperhanger can do is show his face. I read the report. (..)2002 Catch Me If You Can
(..) This is a MICR encoder a machine used to encode bank checks. Do I have an opening bid? HANRATTY: Our unknown subject is a paperhanger who started working on the East Coast. In the last few weeks, this unsub has developed (..)2002 Catch Me If You Can