The book investigates modern architecture as an architectural and cultural heritage, highlighting with a holistic view of sustainability the aspects that have led to epochal changes in the way cities are designed and lived. Currently, many of these buildings spread throughout the world are not recognized as architectural heritage due to the lack of knowledge of innovations in design approaches, materials and building technologies and their social and economic implications in the development of contemporary cities. The main objective is to raise awareness, promote, revalue and preserve the building heritage of the last century through their maintenance and adaptive reuse to the changing needs of the community according to new models of the circular economy and the use of digital technologies. The topics treated with multidisciplinary approaches reconstruct a recent past of which memory has been lost and highlight how the heritage built is a resource of incalculable value that can greatly contribute to the sustainability of cities.