This document discusses controlling as a management function. It defines controlling as a process of monitoring performance and taking action to ensure desired results. The controlling process involves establishing objectives and standards, measuring actual performance, comparing results to objectives and standards, and taking any necessary corrective action. The document outlines different types of controls like preliminary, concurrent, and postaction controls. It also discusses internal and external controls, organizational control systems, and operations management and control techniques. The overall purpose is to explain how controlling is a key management function for ensuring organizational performance meets established objectives and standards.