This book presents a theory of the processes of collective decision-making that draws on theoretical influences, ranging from group decision theory to the authors’ social representations theory. The authors offer an analysis of group conflict and the construction of consensus to produce a general theory of collective decisions. Going beyond the traditional view that compromise is a negative process where group members merely comply in order to sustain cohesion, the authors argue that the conflict at the root of group decisions can be a positive force leading to changes in opinion and innovation. Their theoretical framework is illustrated by numerous empirical investigations from around the world, these outline the necessary conditions required to generate consensus and thus to construct new social realities. The text should be of interest to social and organizational psychologists, management scholars and anyone working on inter-group relations and conflict issues.