Murray Rothbard was the master of reducing complicated theories to their very essence while retaining theoretical rigor, and this essay on Austrian business cycle theory is a case in point. Its continued relevance speaks to an aspect of the Austrian theory that other theories can't boast. It is a real theory that applies across time and place, and its persuasive power is not contingent on the particulars of any individual boom bust cycle.
This audio essay, read by Gennady Stolyarov II, is found in The Austrian Theory of the Trade Cycle and Other Essays (pp. 65-91) edited by Richard M. Ebeling.