Bob goes solo to explain the contributions of Carl Menger and Ludwig von Mises to monetary theory. He then deals with the critique of David Graeber, who argues that the economists' story of the origin of money is bogus.

Bob's Article, "Origin of the Specie": https://Mises.org/HAP464a
R. A. Radford, "The Economic Organisation of a P.O.W": https://Mises.org/HAP464b
Bob's Book, Understanding Money Mechanics: https://Mises.org/HAP464c