This curricular unit aims at conveying the main themes and questions that define Ontology so that students become aware of the conceptual network of this field; thereby increasing their analytical, critical and reflexive skills arising from the main theories. Therefore, the respective objectives and abilities are: To recognize the specificity of ontology and metaphysics; To analyse the implications of the different paradigms; To comment on some of the masterpieces in the philosophical tradition, from the classics to the contemporary; To raise awareness of the link between theory and practice; To identify knowledge and its main concepts; To foster critical reflection.