This document provides an overview of enterprise resource planning (ERP) systems. It defines ERP as software that integrates business functions across an enterprise, discusses the history and evolution of ERP from separate systems in the 1960s-1980s to integrated ERP in the 1990s, and outlines the main components or modules of a typical ERP system, including accounting, human resources, manufacturing, project management, customer relationship management, and supply chain management. The document also covers ERP implementation options, vendors, advantages, disadvantages, examples of successful implementations, and reasons why ERP projects fail.