This paper has as its main objective the critical analysis of certain influential definitions of public policies that exist in the scientific literature of the field. This analysis intends to trace the change in the way public policies are seen, studied and evaluated. The paper in question also investigates the historical context and the process of the birth of public policies, identifying the key factors of a structural, economic, cultural and political nature. The originality of our approach consists in grouping these factors within explanatory paradigms of the emergence of public policies: the structural paradigm, the social control paradigm, the utilitarian paradigm (which includes both economic and social-political pragmatism), the political mobilization paradigm, the humanistic and anti-oppressive paradigm. We first analyze the metamorphoses of the two concepts: public and policies. Later, we bring together the analysis of the historical evolution of the two respective concepts within the framework of the same approach. The conclusion underlines the fact that public policies are socially constructed. The methods used were from the category of those based on secondary qualitative analysis: bibliographic analysis, concepual analysis, discourse analysis, processual analysis and hermeneutic analysis.