General

Item descriptions thief books

Hi, so there's three mastery skill books that are very confusing in the description on basil.
http://www.basilmarket.com/MapleStory-item-Venomous-Star---Stab-20-3034.html
http://www.basilmarket.com/MapleStory-item-Venom-30-3035.html
http://www.basilmarket.com/MapleStory-item-Venomous-Star---Stab-30-5919.html
For Venomous star and stab, the description says [b]for dualblades only.[/b]
For 4th job thieves, venomous star and stab are skills for Shadower and Night Lord, dual blades dont throw stars do they?
So, i just wanna be clarified which skillbook is for which job and such and such.