First principles? You're not going to beat: http://en.wikipedia.org/wiki/Naive_Set_Theory_(book) It starts with defining what a set is, then builds up from

First principles? You're not going to beat: http://en.wikipedia.org/wiki/Naive_Set_Theory_(book) It starts with defining what a set is, then builds up from there while being completely contained. No knowledge is assumed and could be enjoyed by someone with high school maths.