Full Idea
To know something's essence is not to be acquainted with some further thing of a special kind, but simply to understand what exactly that thing is.
Gist of Idea
Knowing an essence is just knowing what the thing is, not knowing some further thing
Source
E.J. Lowe (Two Notions of Being: Entity and Essence [2008], 2)
Book Reference
'Being: Developments in Contemporary Metaphysics', ed/tr. Le Poidevin,R [CUP 2008], p.39
A Reaction
I think he is wrong about this, or at least is working with an unhelpful notion of essence. Identity is one thing, and essence is another. I take essences to be certain selected features of things, which explain their nature.