GameBanshee Forums

I stumbled across this fun little fact earlier today by accident.

If you sell a skill book to a vendor they will then always have a copy of it when you go to visit them, like Trip does with the 2 he sells, so with a variety of books you can sell and buy twice to get both points of them.

Yeah, I noticed this too..
This is how it goes:

1)Sell a book to ex. Trip
2)Rebuy it from him
3)Use or drop the book and then go to the Buy menu to buy another book!