I got a Data Structures book from a professor (I'm in Information Systems, btw) who teaches Computer Science. I told him I wanted to learn more about CS, and he told me Data Structures are pretty much the bread and butter of CS. The very first chapter is Big-O, but it seemed so heavy with math, especially logarithms, I couldn't understand it. I'm sure with a few weeks of studying I could start getting a grasp of it, but when you're going higher education in CS, how important is knowing that? The rest of the book seemed easy, though.