This document summarizes the work of Herbert Alexander Simon, an American social scientist known for his work on administrative decision making and organizations. It outlines Simon's influential 1947 book "Administrative Behavior" which sought to replace the classical economic model of single, profit-maximizing decisions with an approach that recognizes multiple factors influencing decisions. The document then describes Simon's concepts of the "Economic Man" who makes fully rational decisions, and the "Administrative Man" who uses simplification and rules of thumb to make decisions in the real world.