The document discusses the three divisions of manufacturing industry: heavy, light, and high-tech. Heavy industry involves refining raw materials like minerals and metals on a large scale, often over large areas of land, and can cause pollution. Light and high-tech industries are more "footloose," having fewer constraints on location due to smaller facilities and lower raw material needs. They are located in pleasant areas near transportation and markets. High-tech industries also locate near research centers and universities to stay innovative in fast-changing fields.