This document provides an overview of Alderfer's ERG Theory of motivation. It begins with defining motivation and listing factors that influence it. It then discusses Maslow's Hierarchy of Needs and introduces Alderfer's modification called the ERG Theory. The ERG Theory categorizes motivational needs into Existence needs, Relatedness needs, and Growth needs. It describes each need level and explains the relationships between levels, including satisfaction-progression and frustration-regression.