The study of noncommutative rings is a major area in modern algebra. The structure theory of noncommutative rings was originally concerned with three parts: The study of semi-simple rings; the study of radical rings; and the construction of rings with given radical and semi-simple factor rings. Recently, this has extended to many new parts: The zero-divisor theory, containing the study of coefficients of zero-dividing polynomials and the study of annihilators over noncommutative rings, that is related to the Köthe's conjecture; the study of nil rings and Jacobson rings; the...