See E. A. J. Johnson, Predecessors of Adam Smith: The Growth of British Economic Thought (1937).
Mun began his career by engaging in Mediterranean trade, and afterwards settled in London, amassing a large fortune. He was a member of the committee of the East India Company and of the standing commission on trade appointed in 1622. Mun’s time as the director of the East India Company coincided with a silver shortage in England, and he was called on to defend the company’s practice of exporting large amounts of silver.
Mun’s 1621 work, A Discourse of Trade from England unto the East Indies, is in a large part a defense of company practices. However, it is for his work England's Treasure by Foreign Trade that he is best remembered. Although written possibly about 1630, it was not given to the public until 1664, when it was “published for the Common good by his son John," and dedicated to Thomas, Earl of Southampton, lord high treasurer. While Mun is often compared favorably to Josiah Child, another classic mercantilist, England’s Treasure was considered to be a direct repudiation of the arguments of Gerard de Malynes. In it we find for the first time a clear statement of the theory of the balance of trade.
According to Mun, trade was the only way to increase England’s treasure and in pursuit of this end he suggested several courses of action: frugal consumption in order to increase the amount of goods available for export, increased utilization of land and other domestic natural resources to reduce import requirements, lowering of export duties on goods produced domestically from foreign materials, and the export of goods with inelastic demand because more money could be made from higher prices.