This book provides a fascinating study of the very important emerging field of direct reduction in which iron ore is ‘directly reduced’ in the solid-state, using either natural gas or non-coking coal, to produce a highly metallised material, referred to as sponge iron (or direct reduced iron). This intermediate product is subsequently melted in electric arc furnaces or induction furnaces (sometimes even in basic oxygen furnaces) to produce liquid steel. Such a process combination enables steel to be produced without using coking coal, which is an expensive input in the normal blast furnace—basic oxygen furnace route of steelmaking adopted in integrated steel plants. The book offers comprehensive coverage and critical assessment of various coal-based and gas-based direct reduction processes. Besides dealing with the application of the theoretical principles involved in the thermodynamics and kinetics of direct reduction, the book also contains some worked-out examples on sponge iron production. The concluding part of this seminal book summarises the present and future scenario of direct reduction, including the use of gas generated from coal in direct reduction processes. The book is primarily intended for the undergraduate and postgraduate students of metallurgical engineering. It is also a must-read for researchers, technologists and process metallurgists engaged in the rapidly developing field of direct reduction of iron oxides, which is of critical importance for India and other developing nations that are beginning to play a major role in global steelmaking.