The author argues that the practice of devaluing the currency by change in its metal content was a big mistake. He warns that almost never depreciates the currency without ruin to the nation and that this apparent profits involve multiple disasters, tied to even greater losses in the future. He also criticizes the kings who levy taxes on people without their consent. The author discusses the duplicity of the value of money: it is intrinsic and natural, from the condition of metal and its weight, to which would add the work of wedge it and the engine to do it, and it's nice and extrinsic, when constituted by law of the prince, which establishes monetary values, as well as the prices of other goods. For him, those in power must take care that these two values are identical and not differ each other.