This conclusion presents some closing thoughts on concepts discussed in this book. The book illustrates that the retrofitting of cities encompasses a wide range of perspectives, activities and social interests. It discusses variety of retrofit responses and the basis for comparative exploration of retrofitting in and at city-scale. Four key themes explained in the book are Retrofit that is a concept with significant interpretative flexibility and multiple framings, Retrofit that is about existing context as well as changing context, Struggles over retrofitting context, Governing retrofit that involves experiments at scale and with new forms of organisation. Retrofit is commonly viewed primarily as a technical and economic feasibility issue and often focuses on a building or group of buildings. It also often emphasises a language of transformation and reconfiguration.