In 1764 Smith devoted time to developing his thoughts on economics. During this time period, governments were active in granting monopolies and controlling foreign trade. In 1764-66 Smith made a grand tour of the European Continent as the tutor to the young duke of Buccleuch. While in France, Smith, spent considerable time in Paris, where he met with Quesay, the founder of the Physiocratic system. He discussed economic issues with these leading French intellectuals. Smith described the Physiocratic system as close to the truth of political economy that has yet been published. After returning to Scotland, Smith settled back in Kirkcaldy and spent the next ten years working entirely on the composition of his greatest work, The Wealth of Nations. It went through many editions during his lifetime with much small change and only one new chapter. During this time period the British Colonies were in rebellion, and the races of India were being brought under British domination. Smith did not invent economics. Joseph Schumpeter observed that "The Wealth of Nations" did not contain "a single analytic idea, principle or method that was entirely new." Smith's achievement was to combine an encyclopedic variety of insight, information and anecdote, and to distil from it a revolutionary doctrine. The resulting masterpiece is the most influential book about economics ever published. Remarkably, much of it speaks directly to questions that are still of pressing concern. Smith's major thesis in the WEALTH OF NATIONS was that, except for limited functions (defense, justice, certain public works), the state should refrain from interfering with the economic life of a nation. Another main idea that Smith puts forward in Wealth of Nations is that specialization will make a nation and people wealthy. "The greatest improvement in the productive powers of labor (seems to have the effects of the division of labor.