Bon apetit Nexon...

Doesn't matter if they're dropping or not. You would have to REALLY not care about your character to pass up the NX books. I'm not a damage whore or anything but the idea of missing out on 2 SP per skill (so what is that like 12 SP total?) would drive me nuts.

I think the skills that have CS books are only locked once, not twice (Slash Storm locks at 5 and requires 1 book, and Mirror Image probably locks at 15 and requires 1 book, since there's only an MI30 book in CS). Still, free SP is free SP.