Morris and Linda Tannehill were two libertarian activists and thinkers who, in the early 1970s, made surprisingly profound advances in the theory of the stateless society.
Their free-market manifesto, The Market for Liberty, was written just following a period of intense study of the writings of both Ayn Rand and Murray Rothbard; it has the pace, energy, and rigor you would expect from an evening's discussion with either of these two giants.
Ludwig von Mises: ". The use of money in a market economy is a praxeologically necessary fact. That gold, and not something else, is used as money is merely a historical fact and as such cannot be conceived by catallactics." - Human Action