Hecke was certainly one of the masters, and in fact, the study of Hecke Lseries and Hecke operators has permanently embedded his name in the fabric of number theory. It is a rare occurrence when a master writes a basic book,and Hecke＇s Lectures on the Theory of Algebraic Numbers has become a classic. To quote another master, Andre Weil: "To improve upon Hecke, in a treatment along classical lines of the theory of algebraic numbers, would be a futile and impossible task."