Does Dual Blade Cs skill books Drop From Mobs or Not???

people keep saying they might be droping from monsters can anyone conferm this with a screen shot.
or anything...

http://www.southperry.net/showthread.php?t=29750

They drop. I saw Flying Assaulter, Mirror Image and Tornado Spin in the FM. Not sure about Slash Storm, though.
EDIT: Ninja'd.

c

To get it higher level than 5 you need the cs book dont you? Thus making that useless...

To get it higher level than 5 you need the cs book dont you? Thus making that useless...

Mirror Image goes to level 10 before a book is required.

And storm slash requires level 5 to use storm 20. DB books are different in that

level 5 to make it level 20
level 10 to make it level 30

They only have 1 book per skill that requires a book. A zak 10 book will give all 30 levels immediately.