This is a very valuable book for me, the most attractive thing for me was on how you can measure the value of any country, it's not only by gold or liquidity, it's by the imports and exports plus the national productivity and GDP.
In the book, the author consists that people were born with the mentality of trade and exchange for good, but when the humanity started to have countries and governments, things started to change to see the role of each part of them, gouverments role is only to make sure that all is going good with the regulation without a direct effect by its side, it can't be a huge part of the economy.
Another point the author talked about is how to measure the value of anything in our life ( usable or transferable ) plus how we should divide the work by putting the specialist in their own roles in the best time to get the best results.