If you have worked with C or Java, there's no reason that you shouldn't be able to follow a book written with Pascal as its language. If you haven't, then Pascal is still an excellent teaching language that would serve as a pretty decent lead in to C or Java.
I know Java enough to use Processing--which isn't a whole lot. My C is passable. To be honest, I didn't read a whole lot of it. I expected it to get harder that thought I'd ask around before I invested more time.