What is the theme in Metal Men: Marc Rich and the 10-billion-dollar Scam by A. Craig Copetas?

The metals trading market is the main theme in the book. Of all the world's commodities that are traded, one stands apart from the others. The metals trading market, which loosely includes oil, is a murky world in which the earth's precious metals are bought, hoarded and sold for profit. Since its existence, the metals market has kept secret many of their deals and methods of operation. Many traders do not understand the entire process of shipping and distribution once they make a deal. If metals trading executives were asked to provide a job description of a metals trader, many would be hard-pressed to do so.