This article examines the phenomenon of the crime novel in Spain from the perspective of the tension between the realism that is said to be a characteristic of the genre and its antecedents and generic aspects. On the one hand, the crime novel is a radical genre: it reaches out much farther than the neo-realist or experimentalist novel, it analyzes corruption in the capitalist and political life, it uses metafictional concepts, quotes, intertextuality, and other so-called Postmodernist characteristics to question the notion of the novel as purely mimetic art. But its social radicalism and its questioning of the novel as a genre are restricted by its use of the conventions of the North American novel, of the noir films, and of the crime novel motifs. In this way, then, a supposedly radical form turns out to be, in many aspects, more or less conservative and even reactionary, as for instance, in relation to women, social order and human relationships. This article suggests that from this tension the originality and the distinctive character of the Spanish crime novel are born.