General

wait, so you can use books that are not your class and exchange them for ones that do?

if so better stock up on cheap books and go on a mmb run

Watch nexon not release it and the good of red.

Thank you. I was reading half truths and half lies. </3

Yes they are
you don't need skill books anymore, they'll be available as soon as you get job advance
As for mastery books, there will be NPC sellin a book lv.20 and lv.30, using one of them will open a window allowing you to choose a skill you wish to upgrade
(lv.20 = 7m, lv.30=10m)
Oh and once RED arrives, you'll be able to trade old books with new ones through Maple Admin, so dont throw them