This book attempts to apply my know-how on High Speed Rail (HSR) systems, gained since 2008, in analysing and quantifying some impacts brought by them. Specifically, through the case study of the city of Naples, in the south of Italy, I will focus both on the direct and indirect impacts of these systems. Indeed Naples is an important node of the Italian HSR network. In Chapter 1 the question of mobility impacts is analysed on the HSR link between Naples and Rome, i.e. the shift between car and train is reported. The results obtained from this study have been used to make a further reflection on the question of the role of HSR systems in fostering the formation of megacities and megaregions. Chapter 2 investigates the link between HSR systems and the tourism market. The main factors influencing tourists’ destination choice are highlighted and the impact of HSR systems on this choice is widely investigated. Chapter 3 focuses on the relationship between HSR stations, service innovations and temporary office spaces for mobile workers. Conclusions are finally reported together with further perspectives concerning the question of HSR systems and social exclusion.