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.
(..) This essentially was a false alarm. The radar appeared solid. - How long till it's fixed? - minutes, tops. Sounds good. What drives me is the unknown. What if we could predict the tornado's path? How many lives would be spared by an early warning system? And D.O.T. ... (..)1996 Twister