Industry is the production of a good or service within an economy. Manufacturing industry became a key sector of production and labour in European and North American countries during the Industrial Revolution, upsetting previous mercantile and feudal economies. This occurred through many successive rapid advances in technology, such as the production of steel and coal.

Following the Industrial Revolution, perhaps a third of the world's economic output is derived from manufacturing industries. Many developed countries and many developing/semi-developed countries (People's Republic of China, India etc.) depend significantly on manufacturing industry. Industries, the countries they reside in, and the economies of those countries are interlinked in a complex web of interdependence.

Industries can be classified in a variety of ways. At the top level, industry is often classified into sectors: Primary or attractive, secondary or manufacturing, and tertiary or services. Over time, the fraction of a society's industry within each sector changes. They are-

PrimaryThis involves the extraction of resources directly from the Earth; this includes farming, mining and logging. They do not process the products at all.
SecondaryThis group is involved in the processing products from primary industries. This includes all factories—those that refine metals, produce furniture, or pack farm products such as rice.
Rertiary This group is involved in the delivery and sale of goods. They include truck drivers and retail workers.