This document provides an overview of the history and evolution of organizational systems from calculation systems to integrated enterprise resource planning (ERP) systems. It discusses the transition from single purpose mainframe systems in the 1950s-1980s to functional departmental systems in the 1975-2000 period to modern integrated ERP systems. The benefits of ERP systems include a common set of integrated data and processes to help with decision making and planning across departments. However, ERP implementations are also very difficult, costly, and time-intensive projects that require careful planning and change management to be successful.