Strange! Maybe look in your Logbook to read over again what that Goblin says if you mindreading him! I though he mention a name of a book? So take that book

But sorry, it is already a time ago when I was there!
Maybe you can read this page of a Guide?
But warning: this can destroy your fun, but on the other hand, days of searching also can destroy your fun wink :
http://guides.gamepressure.com/divinityiiegodraconis/guide.asp?ID=8174

On 7th of february 2015 : I start a new adventure in the Divinity world of Original Sin,
it's a Fantastic Freaking Fabulous Funny ... it's my All Time Favorite One !