Quality Function Deployment (QFD) provides a sound understanding of what should naturally occur in design. Its principles are essential knowledge for design and system developers. We can apply QFD to any project that, for one, is a development activity and, two, has a definable customer. This includes products, parts, materials, services, events, software and websites. The book describes the 4-phase QFD approach. The approach conforms to the ISO 16355-1:2015 guidance standard. The House of Quality is explained, as a planning tool for transferring the priorities in customer and stakeholder requirements into the final product. The book further introduces some development tools and techniques often associated with QFD. The Appendix provides a walk-through example of the evolved 4-phase QFD approach, demonstrating the workings of the House of Quality and tools. The Appendix further illustrates a 4-phase QFD example using a simplified substitute for the House of Quality.