The document discusses cost of quality and its categories. It explains that cost of quality refers to the costs incurred to prevent non-conformance and the costs associated with poor quality. There are two main categories - costs of achieving good quality like prevention and appraisal costs, and costs of poor quality like internal and external failure costs. Measuring these costs helps identify opportunities to improve quality and reduce costs. It provides an example of measuring quality costs at a motor company over four years which showed prevention costs increasing and overall quality costs decreasing as quality improved.