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.
(..) outside of being able to see them and hear them, the heptopods leave absolutely no footprint. The chemical composition of their spaceship is unknown. The shell emits no waste, no gas, no radiation. Assuming that the shells communicate with each other, The air between the shells is untroubled (..)2016 Arrival