Economics of Freedom: Austrian School
If you want an excellent grounding in economic theory, try reading Human Action by Ludvig von Mises. Be warned, however, it is not easy going. I consider myself pretty well read with a good vocabulary but if you don't know what praxeology or epistemology are then get an unabridged dictionary and be prepared to use it! Here is a good source for the book:
Another author that heavily influenced my thinking was F. A. Hayek. His classic, The Road to Serfdom is an eye opening cure for socialists everywhere.
Ludwig von Mises
Fredrich von Hayek
