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.
(..) - Affirm. - Got it. Memphis General, medical unit . We're inbound with a male police officer with severe facial lacerations. Weapon unknown. We've got grand mal seizure activity but he's post-ictal now. Vital signs are good. Pressure is over . - ? - Yeah, that's right, . Pulse . (..)1991 The Silence of the Lambs