Second grade, my mother took me to a library which was closing and they were selling off a lot of books. We got this for two dollars. It had pictures and the name was simply "Mathematics", so it was what I wanted. Had the name been more complicated I might have moved on.

Anyhow, this is a general survey of math complete with pictures of what is going on, and how it can be seen in the real world. It really helped develop my math mental picture for how a lot of things worked well before I ever got to that level of math.