Abstract: Fundamental reactions and phenomena in coal carbonization process are reviewed mainly from the view point of coke making. Mechanism of coal pyrolysis, especially formation of tar and gas, was described and changes in the yield and composition of gas with the rank of coal and carbonization temperature were explained.Strength of coke is influerced not only by caking properties of coal, but also by fissures produced during coking, which depend on the rank of coal, i.e, volatile mattcr content of coal. Blending theory for making hard coke was briefly summarized.