Man, Economy, and State
Rothbard systematically and rigorously develops all of economic theory from the axiom that human beings act to achieve ends in a world in which specific and delimitable causes have specific and delimitable effects. In so doing, he has written a work that, over three decades after its publication, still serves as a comprehensive introduction to Austrian School economics.
If you fancy reading more, you don't even have to pony up the dough, as you can read Man, Economy, & State free online at Ludwig Von Mises Institute.
Now you are probably asking -- if indeed you are still reading -- why a nice mommy-blogger like me is troubling my already-dazed and formerly-pretty little head about such things. Because, Austrian Economics makes sense to me, and, when carried to its logical conclusions, supports a very hands-off federal government.
Which brings me to a personally exciting and once-(thus far)-in-a-lifetime announcement: I have finally found someone to vote for that I can believe in.