What did Adam Smith argued in the Wealth of Nations?

In Wealth of Nations, Adam Smith argued for a market system beyond the mercantilism of the day.

Before Adam Smith, the world thought of the world economy as a fixed pie. Countries would fight for dominance on slices of the pie. As a result, Government controlled much of the market.

Adam Smith came in and argued in Wealth of Nations for a free market wherein individuals would work to further their own interests, allowing the markets to grow.