This book it has its direct origin on an international call for papers, issued by Pedro Costa and Paula Guerra, which aimed to give body to a publication on the thematic of creative milieus and cultural scenes in contemporary urban spaces. The organizers of that publication were surprised by the great quality and interest of the proposals for papers which were presented, even if many of them were not focused specifically and directly on the "creative milieus" and "urban scenes" approach they were looking for. Interestingly, many of the papers raised the issue of the relation between urban interventions (particularly street art approaches) and public space. That was so stimulating that the authors, drawing also upon previous work on that area, decided to give birth to another project, complementary to the edition of the original idea of book, which would be specifically focused on issues of urban interventions, street art and public space. For that, they joined Pedro Soares Neves, which have been working for years in the field of street art and urban interventions, is executive director of Urbancreativity international research topic on Graffiti, Street Art and Urban Creativity. The diversity of contributions put together in this book acknowledges the variety of debates and perspectives that mark contemporary discussions on the relation between art and public space, with particular reference to the case of graffiti and street art, which attracted most of the contributors that came from various disciplines and backgrounds.