This chapter aims to describe the origin and current status of quality assurance (QA) in health care and to provide a background of similar developments in other industries, which have provided a major impetus for QA initiatives in health care. The interest in quality and safety in the health care sector has rapidly risen over the past decade. Without important lessons learnt from other industries, the interest and obtained improvements would have been far less fast. Knowledge on basic principles and challenges faced by other industries like the airline, car, and nuclear energy industry, that drove quality improvement projects, is of major relevance to understand the evolutions taking place in health care. To fully appreciate the QA movement, and design or implement quality improvement projects, its basic principles need to be understood. This chapter aims to give insights in basic principles underlying QA, and to discuss historical lessons that have been learnt from other industries. Furthermore, it discusses how to implement and assure a sustainable QA program.