Whether you are a patient, family member, clinician, professional staff member, leader, or management team member, we all want the same thing. We want access to safe and timely urgent care when it is needed, and we want that care to be high-quality, compassionate, and culturally responsive. There have been many changes in Emergency Department care delivery over the years with the evolution of technology, innovations in the clinical evidence base, role development, and standardisation in care, coupled with increasingly complex patient needs. These changes have been based on a reductionistic approach – that we can improve the system by improving the efficiency of its parts. However, improving the efficiency of parts of the system has not resulted in what we want. Therefore, it is time for a shift in thinking to address how the parts of the system interact, and design for what we want – good community health and well-being. In this chapter, we will focus on the journey through discovery, design, and realisation of improving complex systems, illustrating it by examining Emergency Department care delivery.