axiom

Economics in One Lesson, by Hazlitt

The famous abortion-crime link.

Freakonomics is a great book

Freakonomics, by Levitt and Dubner (this book is just so damn fun to read)

Free to Choose: A Personal Statement, by Milton and Rose Friedman

Probably one of the most interesting books I've read in my entire life, even if I don't entirely agree with the thesis.