Throughout the History, the thought about the economy had changed. For long time, the economy was limited to trade, war being a different way to make trade!
In the early XVIIe century, some French thinkers, with François Quesnay as their leader, were the first to develop a coherent thought about that subject; they called themselves the Physiocrats; their opponents called them the Economists!
Later, the British used their knowledge to develop a powerfull country and a world empire with the lead of Smith and Ricardo.
Today, the whole world use this science to get a better life. From the first thinkers, centuries ago, to the new thinkers, we may divide them in three groups according to their vision of the economy. So we have three schools of thought: