This introduction presents an overview of the key concepts covered in the subsequent chapters of this book. The book contributes to the international discussion and in particular to the debate on the necessity of a new urban theory. It discusses some of the most relevant methodological challenges related to the exploration and interpretation of the current forms of the contemporary urban world. The book offers an updated portrait of contemporary Italian urban phenomena. It provides the main methodological challenges related to a key output of the PRIN research: the 'Atlas of post-metropolitan territories' designed and implemented with the ambition to build an observatory on urban regionalization processes in Italy. The book focuses on the r...