Historical research on processes of transition to democracy since 1974 has shown the limitations of studies carried out by social scientists. It is time to vindicate the role of historians, who are able to establish comparisons without sacrificing singularities. In order to study the coexistence of authoritarian and democratic institutions and behaviour it is essential to examine the «old» -the political regime to be replaced; describing how the «State with Law» was deconstructed so as to establish the «Rule of Law»; and finally to appreciate the role played by civil society and its influence in the decision-making process. It is also crucial to investigate how to deal with the autonomy of the armed forces and the eventual liability for the violation of human rights by the authoritarian regimes. In short, the idea is to clear each case of the uncertainties that determine the process of transition to democracy.