This work is concerned with the coverage of Le Monde during a troubled historical phase: the Algerian war under the Fourth Republic. The Algerian war, Le Monde and the French Fourth Republic are all keypoints of reference in French political life and cultural. Based on a corpus representing the entire output of Le Monde, this thesis sets out to examine Le Monde's claims that it was at the forefront of the decolonisation struggle. The methodology used is that provided by Laswell's investigative programme, Who says what, to whom and with what effect, updated and adapted for this purpose. The thesis uncovers the newspaper's bias in the portrayal and discussion of the protagonists: the armym the FLN and the civilian populations on both sides of the Mediterranean. An important dimension of the analysis relates to the coverage of civil liberties and the paper's position on the use of wide-scale repression and torture; and discusses the implications for press freedom. The analysis shows that in many respects these were undefended and their champions sacrificed on the altar of national interests and Raison d'Etat. The conclusions reached challenge the view that Le Monde's coverage was critical of government and authority over Algeria, particularly Guy Mollet's administration. The analysis shows how progressive and challenging views propounded by some intellectuals were rejected, or minimised in favour of a more traditional and reforming discourse which did not seriously undermind French prestige. The overall conclusion reached, contrary to conventional wisdom, is that Le Monde did not construct a view of the Algerian war under the Fourth Republic that was fundamentally different from that propounded and circulated by official sources notably by the military. This analysis challenges an on-going myth, that Le Monde's position was both radical and pro independence. This work, written primarily with the British social scientist in mind, combines insight from the historian, the political scientist and the media analyst. It gives priority to the political and historical - rather than linguistic - aspects. It is the only work to span the whole of the Fourth Republic, and the only contribution in English to comprehensively address the political and historical context of Le Monde.