In this volume, the CNAPPC proposes a reflection on a crucial issue in an urban and territorial world plagued by many uncertainties: proximity as a lever for far-reaching transformations. The concept of the 15-Minute City and that of the Half-Hour Territory that I am defending have become relevant elements in the debate on improving the quality of life in our cities in the face of ecological, economic and social challenges. Over and above the number of minutes mentioned, polycentric and multi-service proximity is now at the heart of new ways of changing our lives.