Vilfredo Pareto was an Italian railroad engineer in the late nineteenth century who at the age of 45 decided to become an economist, statistician, sociologist, and demographer. Henry Schultz wrote of Pareto that “those who read Pareto’s original writings will be repaid a thousand fold, for they will then discover how incomplete and misleading is the discussion in most current texts of such fundamental subjects as utility, demand, marginal productivity, and maximum satisfaction, as compared with Pareto’s treatment of the same subjects. They will, in short, learn how classical economic theory has, chiefly through the labors of Walras and Pareto, been unified, amended, completed and surpassed.”
 
Schultz was writing in 1928. Since then Pareto has come to be acknowledged at the Newton of economics, a man who united economics in mathematical form. Most importantly he invented the idea of Pareto Efficiency, upon which all of modern economics is based and which is also the key to uniting economics and politics into a unified view of how society should be organized.

Read more about Pareto at Wikipedia.