I don't know how far are you in math, but to understand set theory it's convenient to have a good notion of what is a function.
Saudações de Portugal.
I've got a book. Introduction to set theory by Vaught. There he says that set theory does not depend on any previous mathematical knowledge. I hope he's right. Hahaha
But i kinda know what's a function, and i guess my basic math knowledge i acquired on school is gonna be enough.
Saudações de Brasil. =)