This address focuses on the analysis of ideas that have contributed to build a psychology oriented towards a way to answer social problems affecting a kind of group present in every society: the community. Because of their human condition communities have a history, are relational and should be understood in their complexity. Community Psychology (CP), in its critical orientation, has looked for social transformation as a way to seek that constant goal of humanity: a better world. To do so, CP has assumed the idea of praxis and, consequently, the ideas of engagement and participation, whose links will be presented in their theoretical, methodological and practical aspects. That transformational praxis is also related with the ideas of power and empowerment (fortalecimiento) understood as the joint construction carried out by psychologists (external agents) and community stakeholders (internal agents), that may lead to conscientization and liberation, two ideas introduced by Freire. These ideas are presented as a theoretical system in which the ethic and political dimensions, together with complexity, constitute the basis for transformation, balance or, fleeting amelioration.