The historical centre of Paris, the Ile de la Cite, is notably home to the Hotel-Dieu hospital, Notre-Dame cathedral, Saint-Chapelle, the Palais de justice law court and the flower market. The core of Paris remains, however, largely unknown. In December 2015, Dominique Perrault, architect of the Bibliotheque nationale de France on the Francois-Mitterrand and the renovation of the Dufour Pavilion at the Chateau de Versailles, and Philippe Belaval, president of the Centre des monuments nationaux, presented a reflection on rethinking the Ile de la Cite with a timeline of 2040. How can this Unesco World Heritage Site, abandoned by Parisians, be modernised and acquire a breath of life and mobility? With its rich collection of archival documents, engravings, maps and photographs, the book highlights the island's various renovation and redevelopment projects imagined throughout history, while questioning its current role. To integrate this exceptional site into the city of tomorrow, Dominique Perrault and Philippe Belaval have imagined 35 proposals that give the island back a central place, notably thanks to the promotion of its exceptional heritage, a revamping of the circulation between its different centres of gravity and the development of its substrata and its foundations as well as its riverside paths.