Antonio Madrid (1968) is Professor of Philosophy of Law at the University of Barcelona. Author of the book The institution of volunteering (Trotta, 2001), its reflection has centered on the analysis of law in social participation mechanisms. This concern has led him to promote, along with other teachers, and to coordinate the project "dret to Dret" (right to justice), which aims to improve the education of students and to promote the realization of the rights of individuals and groups most vulnerable. This book is a step in this line of thought.