Industries can be classified in a variety of ways. At the top level, industry is often classified according to the three-sector theory into sectors: primary (extractive), secondary (manufacturing), and tertiary (services). Some authors add knowledge or even culture and research as fourth and fifth sectors. Paydar Tejarat Zarin’s mission is to develop, provide information and services to all global communities such as companies, suppliers, consumers, all organizations and individuals with an interest in different industries.