This document discusses quality costs in quality control. It defines four types of quality costs: preventive costs for activities to prevent defects, appraisal costs for inspection and testing, internal failure costs for defects found before shipment, and external failure costs for defects found after shipment. The relationships between quality, costs, and profits are explained, with higher quality leading to lower costs and higher profits. Optimum quality is achieved when failure costs are reduced to zero defects.