The book concerns the analysis of participatory practices in support of the decision-making processes. In particular, the research work is based on an important consideration, according to which, traditional participatory processes do not work in practical terms. Indeed, the evolution of the concept of participation reveals that although the implementation of the participatory processes arose from the necessity of strongly criticizing the contemporary society of the 1960's, nowadays they have been used to reinforce and legitimate the existing power relations. In this conceptual framework, participation is currently analysed and interpreted either as a democratic right or as an instrument to achieve specific goals. From this perspective, the research work intends to interpret the intrinsic ambivalence within the concept of participation through the analysis of a case study represented by the Sardinian Regional Landscape Plan (RLP). In particular, the author proposes a procedural protocol, whose aim is to define a methodological framework concerning the implementation of participatory practices in support of the planning processes at the regional scale.