For the Peruvian Nobel laureate Mario Vargas Llosa, contemporary western civilisation is little more than a “civilisation of the spectacle”. Thus reads the title of his latest volume of essays, La Civilización del Espectáculo. In the opening essay, Vargas Llosa cites as a defining image of our age the reported frenzy of paparazzi in New York in September 2008, scanning the skies, on the day Lehman Brothers failed, for suicide jumpers. This grotesque notion evokes not only the 1929 Wall Street crash but also the collapse of the World Trade Centre and Don DeLillo’s “falling man”.

These are very different crises, of course, and Vargas Llosa’s criticism goes further than a mere indictment of media voyeurism. Our civilisation is imperilled not only by a consumerist mentality, which in itself is serious, as it impedes the development of individual judgment and reflection, but by a sense that everything in life is to be judged in terms of the entertainment it provides. If, for Vargas Llosa, the democratisation of culture was born of altruism (a point one might want to debate), then it has simply resulted in banality and frivolity. The scandals at News International are but an example of this broader phenomenon.

These arguments illuminate Vargas Llosa’s semi-fictionalised biography of Roger Casement in The Dream of the Celt, for one begins to see what may have attracted the Peruvian to the story of one of Ireland’s more contentious national heroes. In a world where ethics is reduced to enjoyment, and popular heroes are the designers of technological devices, the example of Casement’s dedication to revealing colonial abuses in the Congo and Amazon rubber trades, as well as his efforts in support of Irish independence, serve to flag up nothing less, for Vargas Llosa, than the erosion of our own humanity. This may sound exaggerated, but The Dream of the Celt is ultimately a eulogy to those who dare to dream a better world, beyond the bounds of political, social and cultural commodification.

Vargas Llosa’s title, of course, echoes Casement’s own epic poem of the same title. There are various dreams in this story of “the Celt”: of a more equitable global order, of Irish independence, of unattainable love. There is also the idealistic and impossible dream of a natural world untouched by human destruction, be it the rugged beauty of Murlough Bay, on the Antrim Coast, near Galgorm Castle, where Casement spent summers as a schoolboy, or the lush and rather threatening vegetation of the Congolese and Amazonian jungles. Finally, there is Casement’s mourning for his mother, who died when he was nine and whose memory haunts him as he embraces Catholicism at the end of his life.

Vargas Llosa has divided Casement’s life into three sections, each reflecting one of his political and social dreams: the Congo, the Amazon and Ireland. Chapters alternate between those in which Casement reflects on his life as he awaits execution in Pentonville Prison, in London, in 1916, and those in which he investigates colonial abuses in Africa and South America, or negotiates arms from the Kaiser’s Germany to assist in the Easter Rising. There are obvious echoes of Joseph Conrad’s Heart of Darkness, as well as specifically Latin American resonances, from the Cuban Alejo Carpentier’s The Lost Steps and the Argentinian Manuel Puig’s Kiss of the Spider Woman.

Irish readers will be familiar with Vargas Llosa’s reiteration of the heroic nationalist vision of the 1916 rebels - curious, given the author’s strident criticism of nationalism in other writings. However, his emphasis on the English liberal heritage as regards human rights and his treatment of the infamous Black Diaries may prove more thought-provoking.

Much attention is paid in The Dream of the Celt to stressing not only colonial abuses but also Casement’s role as an agent of the British crown in investigating them. With his strong links to London figures such as the anti-slavery campaigner ED Morel, Casement’s life reveals not only the stereotypical “heart of darkness” of colonialism but also the opposition to it right at the centre of the British Empire. This is significant, for at a time when the role and nature of empire are being re-examined, Vargas Llosa’s novel does not allow for an easy divide between colonisers and colonised, the Irish case included.

Vargas Llosa’s novel is also interesting for its treatment of Casement’s sexuality and the controversial Black Diaries. Rather than judging these to be wholly false, and so a matter of English propaganda, or wholly true, Vargas Llosa (perhaps, as a novelist, closely attuned to the interplay between fiction and reality) reads them as a mixture of factual diary and escapist fantasy. In this sense, they reflect the profound loneliness that the prison chapters in The Dream of the Celt convey so movingly. At the end of the novel the author remarks: “Roger Casement wrote the famous diaries but did not live them, at least not integrally There is in them a good deal of exaggeration and fiction.”

This underscores the imaginative leap that Vargas Llosa himself has made in seeking to narrate Casement’s life, particularly his final weeks in prison, with profound empathy and understanding. Admittedly, this limits the narrative perspective, inhibiting any truly searching critique of Casement’s contradictory positions or of his unthinking mixing of human rights with nationalism (Vargas Llosa’s Casement seems curiously impervious to the differences between colonial abuses in Congo or the Amazon, and in Ireland). But for a writer disturbed by a lack of ethical concern in our contemporary world, it permits a romantic exploration of Casement as a tragic hero who, despite his own evident failures, dared to dream.