Picaresque narrative has transcended chronological and spatial limits, according to a series of critical studies. Even literary authors themselves, such as Günter Grass and Thomas Mann, have affirmed that they have written Die Blechtrommel and Bekenntnisse des Hochstaplers Felix Krull respectively according to the picaresque model. One of the aims of this work is to justify the persistence of a type of novel in the XX. century, when it originally arose in the cultural, social, political and literary context of the XVI. and XVII. century Spain. In order to achieve a historical, theoretical and critical study of the picaresque narrative, the first step of this work has been to set the typology of a picaresque novel. Taking three canonical Spanish picaresque novels (La vida de Lazarillo de Tormes, Guzmán de Alfarache and La vida del buscón) as a basis, with references to Simplicius Simplicissimus and The Fortunes and Misfortunes of the Famous Moll Flanders, four relevant features are to be considered axial for the picaresque narrative. First of all, it is in the picaresque novel where the narrative form adopted from the autobiography is for the first time used for fictional, secular and marginal actions. Second, the episodic structure shows recurrent episodes, such as marginal familiar inheritance, orphanhood, initiation, etc. The picaro is the third axial element of this narrative: product of a social and moral conflict, transgressor and trying very hard to progress in life, he finds himself on the borderline at the end of his narration. Last but not least, the four main themes treated in picaresque narrative (Freedom, Guilt, contradictions between reality and appearance, and Fortune) reflect the philosophical, religious, moral and social problematic of the time. All these relevant features are found in the six literary works analysed in this study: Die Blechtrommel by Günter Grass, Bekenntnisse des Hochstaplers Felix Krull by Thomas Mann, The Horse?s Mouth by Joyce Cary, The Loneliness of the Long Distance Runner by Alan Sillitoe, Hijo de Ladrón by Manuel Rojas and Nuevas andanzas y desventuras de Lazarillo de Tormes by Camilo José Cela. Each work contributes, nevertheless, with further features that adapt the picaresque essence to the XXth-century social, intellectual and literary scene. Felix Krull exemplifies a picaresque career with a middle-class familiar background. His world view swings between duality and multiplicity, he tries and achieves to play different identities, he is fascinated with fiction in dramatic representations and references to his resemblance to Hermes in terms of ambiguity and enigma are central in the novel. Oskar Matzerath, main character of Die Blechtrommel, is a very precocious picaro comparing with the traditional one. He ironizes, besides, his own guilt. Dualistic iconography and Oskar Matzerath?s ambiguous relationship with the artistic world make up a thematic complexity inexistent so far. The Horse?s Mouth presents an artist as picaresque model, which implies Jimson?s double marginality (as artist and as trickster), on one hand, and the literary elaboration of the picaresque career with constant symbolic references to paintings and Blakean intertextuality. Alan Sillitoe shows the essence of picaresque philosophy in The Loneliness of the Long Distance Runner. Smith?s loneliness and his world view as long distance runner become a precious metaphor of a picaro?s obstacles and strategic strengths. His reflections on truth, appearance, falseness, honesty, etc. are also in tune with the picaro?s discovery about world?s false surface. While Cela?s work Nuevas andanzas y desventuras de Lazarillo de Tormes makes explicit allusion to picaresque narrative, it actually does not present thematic or formal contributions to this type of novel. Hijo de Ladrón, on the contrary, brings formal innovations to the narrative style, such as the modernistic chaotic narration and fragmentariness, apart from different dimensions to the picaresque philosophy: the picaro?s development and concerns achieve a metaphoric, philosophical and political dimension in the case of its main character, Aniceto Hevia. The innovations of the selected and analysed literary works can be systematically structured. The relationship between the picaresque autobiographer and his audience has changed in the XXth century, which has to be understood in direct contact with the more philosophical and intellectual, rather than moral and social, tension developed between the erlebendes Ich and the erzählendes Ich. The episodic structure shows the adaptation of the action units to the equivalent meanings of the XXth century: familiar inheritance is somehow differently marginal, the picaro?s orphanhood has a more emotional dimension in the modern version, initiation takes place by means of a less physical and more aesthetic experience and the final ambiguous position is more complex. The picaro?s contradictions, which were mainly social and moral in the traditional picaresque, reach a more various range in the XXth century: physical, psychological and intellectual contradictory features of Matzerath, Krull, Smith, Jimson, etc. are related to a new picaresque concept of suffering and pain. His transgression has changed, as the world has changed around him. Central themes are still the same ones, developed on a universal and secular level.