Leonard E. Read was the founder of the Foundation for Economic Education — the first modern libertarian think tank in the United States — and was largely responsible for the revival of the liberal tradition in post–World War II America. Mises.org will be putting all of his books online for free. See them all here.
Ludwig von Mises: "Liberalism, which demands full freedom of the economy, seeks to dissolve the difficulties that the diversity of political arrangements pits against the development of trade by separating the economy from the state. It strives for the greatest possible unification of law, in the last analysis for world unity of law. But it does not believe that to reach this goal, great empires or even a world empire must be created." - Nation, State, and Economy