If asked why his scrolls are so inexpensive, 'Ten-Tongues' Weerhat reveals that they're supplied by Ahnia, and he doesn't ask questions about their origins. When asked about her (stolen) goods, Ahnia quickly turns violent, and this note is subsequently found. If confronted with the note Weerhat is willing to give the book to the Nerevarine, who can return it to Elbert Nermarc in exchange for a small discount at his shop in Craftsmen's Hall.
I've tried so hard, and yet no one has any interest in this blasted book. Perhaps if anyone could READ it, it might sell as well as the scrolls do. If I can't get rid of it soon, I'm returning it to you. I don't want to hold on to it for too much longer, or else people might suspect something.