This document provides an overview of plaster of Paris (POP) casts, including their history, uses, classifications, application process, aftercare, and potential complications. POP casts are made from calcium sulfate and are used to immobilize and support fractures, joint injuries, and corrected deformities. They are classified based on their application (slab, full circumference cast, or spica cast) and involve applying multiple layers over the injury site. Aftercare includes keeping the cast dry and clean while avoiding heat, with potential complications including joint stiffness, pressure sores, and nerve palsy.