Book excerpt: In recent times what has become known as "the case of Medellín " has generated a growing interest in the international community. These urban transformation that Medellín has experimented have become a focus of attention and reference for experts in many fields, around the world. The book ́Medellin: Environment, Urbanism and Society ́, that now published the Center for Urban and Environmental Studies, Urbam, of EAFIT University is a testimony of the value given by our culture to the accomplishments of the city, to the idea of the public sphere and the growing relationship between the technical sphere and the political sphere, understood in the broad sense as a form of disciplinary knowledge and construction of civil society. This book brings together a knowledge of the city from multiple perspectives; knowledge that is, without any doubt, impressive for its extension and profoundity, as well as for its capacity to combine objective data with conceptual reflections about the scope and impact of the different perspectives concerning the theme of urban transformation and the different actors that have participated in such processes. The book weaves a broad net over the city, its history and development, adopting a multidisciplinary vision. I think that this will be the first step in creating a speech that might finally liberate itself from the strict disciplinary boundaries, building a trans-disciplinary perspective that can amplify the urban dimension of the city. This is the beginning of a profound and complex reflection that is, at the same time, a project of knowledge and an instrument of action and participation.