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.
(..) l've awakened from hyper-sleep on a strange planet. -Now what did you do? -l just did what you told me! l'm surrounded by alien creatures of unknown intent. Who goes there? Friend? Or foe? We're all . l must have crash-landed (..)2010 Toy Story 3