Emil Artin was one of the leading algebraists of the 20th century. He worked in algebraic number theory, contributing largely to class field theory and a new construction of L-functions. He also contributed to the pure theories of rings, groups and fields. Artin developed the theory of braids as a branch of algebraic topology. He was also an important expositor of Galois theory, and of the group cohomology approach to the class ring theory (with John Tate), just to mention two theories where his formulations have became an established standard. The influential treatment of abstract algebra by van der Waerden is said to derive in part from Artin's ideas, as do those by Emmy Noether. This volume is a reprint of Artin's works.