The document discusses command systems used in emergency operations. It introduces the Incident Command System (ICS), which was developed in California in the 1970s in response to wildfires. ICS establishes a standardized organizational structure and common terminology to coordinate multi-agency emergency response. It is a modular system with five main sections: command, operations, planning, logistics, and finance/administration. The ICS aims to integrate the different organizations responding to an incident under a unified command structure to efficiently manage resources and improve information sharing. While ICS provides an effective framework when objectives are clear and organizations collaborate well, it also faces some criticism around flexibility and its ability to manage large-scale, prolonged emergencies.