This handbook reports fundamentals, industrial practices and new aspects for the formation and control solution of non-metallic inclusions in different grades of steels. It summarizes the latest research achievements of thermodynamics and kinetics, such as deoxidation of real steels rather than pure iron, precise calcium treatment, prediction of the amount, size, composition and spatial distribution of inclusions in steel continuous casting semis which were rarely reported in other books in this field. It is a useful reference for researchers in steel industries for the control of non-metallic inclusions in steel, and the production of high-quality steels in industries such as automobiles, household electric appliances, bearings, electric transformers, high-speed trains, oil pipes and cutting wires.