Essays / Background of a story at the beginning of an essay about a book? [3]

Is it necessary to say the background of a story at the beginning of a essay on a book? This is my beginning right now:

In Very Far Away From Anywhere Else by Ursula K. Le Guin, the main character, Owen, has invented a fantasy world he calls Thorn.

Can I assume the person reading my essay has read the novella? Or should I include this?

Thank you so much! If you want to read my whole essay, you can (I'm attaching it...).