Fredric Bastiat - "The Law" - http://www.freeaudio.org/fbastiat/thelaw.html (audio book) http://www.amazon.com/Law-Frederick-Bastiat/dp/1933550147/ (5 stars with 83 reviews so it's not just me)

It'll only take about forty minutes to finish.

If you go with a Teaching Company course I highly recommend their "Great Minds" series (though without a library it is a bit spendy): http://www.teach12.com/ttcx/coursedesclong2.aspx?cid=470&;