From September 1970 through May 1971 Tulane University organized a special year long program in the theory of noncommutative rings and operator algebras. Visitors from various institutions of the U.S.A. and abroad contributed to a series of lectures in which they covered recent advances in their own field of specialty. These notes contain these lectures to the extent that they have not appeared elsewhere. This volume represents the purely algebraic side of the program with lectures in the structure theory of ring and modules.