Over the years, governance has been studied in literature on different aspects and perspective theories to try to conceptualize it but a shared definition has never been formulated. In the beginning, the concept arose in the social science debate focusing on the transition from government to governance. It described the decentralization of powers and functions towards the local government, especially in the planning field. With the years passing, scholars focused on which institutions received the powers from the national government and the interrelationships between the institutions involved in the process. Other scholars have tried to identify possible typologies of governance to try to conceptualize and operationalize it. More recently, others have focused on the territorial aspects of governance underlying the importance of the territory as a resource for the urban development and as a fundamental element of governance.

In addition, governance has contribute to the use of informal and formal processes between public and private actors. It also focused on the introduction of new and different ways of implementing planning tools.

The decentralization of powers was directed to different levels of public institutions or to particular urban territories that required new institutions to govern them. These institutions assumed the forms of regional or metropolitan public institutions while others were, for example, associations or union of local governments. They also had the powers to use tools that never existed or were never used before. In the meantime, the State kept is role of guide and, depending on the government system, had different powers and functions. While these changes were happening at the institutional level, the European territories and cities became the objects of numerous transformations. Especially, in the second half of the twentieth century, medium size cities, along with the major European cities, withstood strong suburbanization processes, which already existed since the industrial revolution, for economic and social reasons. Different parts of the populations changed the location of their residency from the central downtown site to the closest small towns. Therefore, those territories, already characterized with a strong urbanization, saw their administrative boundaries erased or confused with the ones from other small towns creating an almost completely urbanized area. In addition, over the years, those small towns became urban centers increasingly appealing for activities or industries while remaining dependent from the central city. These characteristics may be regrouped under the concept of "metropolitanisation", which is the tendency of a general integration of urban areas with their closest territories.

The areas, which are the object of "metropolitanisation" process, are characterized by a strong central city from which the other small towns depend from characterized by a strong interrelationship. They are characterized by territorial and economic dynamics, which need collaborations and cooperation between the public institutions included in the area in order to achieve a well-balanced system. The need of collaborations between public actors, the influences of private actors and the shared programming have allowed the arising of a perspective theory of governance, to explore which tools are more appropriate to the governing of these areas: metropolitan governance.

In the last decades, metropolitan governance has been the object of different changes and transformations. The institutions of metropolitan areas have changed; sometimes they were born because of top-down processes, which means they were created by the national government, while other institutions arose from a bottom up process, which means from a local territory. From the 90s, new forms of regional coordination and new type of metropolitan institutions came back in the center of the political debate and they focus on the economic side of the development of the urban systems. The competitiveness of their area had the aims of reaching international and global markets.

To better understand the elements and factors of governance, this thesis focuses on two case studies, the metropolitan city of Turin and the Hanover region, to highlight their positive and critical elements. The analysis touches upon two different levels: the overall governance framework for metropolitan governance and a number of selected planning tools. The aim of the thesis is therefore the identification of positive and negative elements of metropolitan governance in order to recognize the factors that can be consider useful, in the future, to the realization of a theoretical base which will be applicable to different territorial contexts.

Chapter 1 focuses on the definition of governance and its evolution over the years; it analyzes multi-level governance, governance arrangements and territorial governance. If, on one hand, governance has facilitated the promotion of local resources, on the other hand, it has created the variety of procedures and processes for developing only on the features of a particular territory.

Chapter 2 analyzes governance in the metropolitan areas. These areas have gained a central role in our globalized society. Their competitiveness at international level is brought to light the absence of appropriate collaborations and tools. The chapter studies the historical evolution of metropolitan governance, focusing on the typologies of institutions, the functions, the powers and the actors involved in the process.

The second part of the thesis focuses on the two selected case studies, the metropolitan city of Turin and the Hanover region. The analysis of both cases and their comparison allow for the identification of shared governance elements and of the ones that differentiate them. The analysis is conducted on two level: the governance system and selected planning tools; those are the overall strategies for development, the plans regarding the management of green areas and landscape and the transport and mobility plans.

Chapter 3 describes the adopted methodology, building on the existing literature on the topic. To study metropolitan governance in the selected cases, the thesis adopts the four ideal typical governance arrangements of Arnouts, van der Zouwen and Arts (Arnouts, v. d. Zouwen and Arts, 2011). To analyze the selected planning tools it applies the territorial governance dimensions and indicators produced by the "TANGO_ Territorial approaches for a new governance" research project in the framework of the ESPON - The European Observation Network for Territorial Development and Cohesion (ESPON, 2014).

Chapter 4 describes the urban and metropolitan contexts of the case studies. It analyzes the legislative frameworks at the national and regional level, the historical development of governance's processes in the regional contexts and the selected planning tools.

Chapter 5 analyzes and underlines the positive, negative and common elements that characterize metropolitan governance framework in the metropolitan city of Turin and in the Hanover region. Similarly, it explores the various spatial planning tools and their governance implications. The observation of the two areas and of the instruments at stake is guided by the methodology described in chapter three allowing the recognition of the recurrent elements of the processes of governance.

A final section rounds off the contribution, comparing the two case studies and the tools under investigation, as well as reflecting over more general implications for the future of metropolitan governance in the selected contexts as well as in Europe.

All in all, the analysis shows how the governance approach constitute a "most suited framework" to understand that dynamics that characterize the steering of spatial development processes in complex territories. The study of the different typologies of governance highlights the necessity for a general theoretical approach to governance, to be used as a key reference to identify good practices that may play a relevant role, in every territorial contexts.