This article is an essay review on two recent books about Spanish Constitutional History. At his work Joaquin Varela analyses the relationship between constitutional ideas and the liberal political culture in the Modem Spanish History. From the scholastic iusnaturalism - Martinez Marina - to the revolucionary liberalism -Arguelles, Florez Estrada-, postrevolucionary liberalism -Balmes, Pacheco, Donoso- or later in liberal democracy, the development of the Constitutional History was extremely complex. Under the influence of the scholastic iusnaturalism, nationalist historicism and the krausistic ideas, the arrival of juridical positivism in the Spanish political culture was weak, as the juridical ideas of Adolfo Posada have shown. This essay let him to check hard lines which ruled recent historiography about Spanish liberalism. At the same time Varela tries to set up Constitutional History as academic discipline in Spain.