After a series of teaching jobs and work as a journalist, Vallejo left Peru for good in the middle of 1923. By that time, his deeply loved mother was dead and a passionate love affair had ended acrimoniously. Vallejo went to Paris. There, with little money, no contacts and no French, he somehow managed to eke out a living with journalism and some teaching. In time, of course, he made friends and it was in Paris that he became radically political. He studied Marxism and visited Russia three times in the 1930s to observe for himself the great Soviet experiment in social engineering. And he married a French girl, Georgette Philippart.

When the Spanish Civil War broke out in 1936, Vallejo passionately committed his time and energy to the Republican cause, writing propaganda and acting as a political instructor. He was in Spain in 1936 and again in 1938 when he attended the International Congress of Anti-Fascist Writers. What he saw in Spain during these visits made him fearful for the fate of the Republic while his fervour for the Republican cause increased rather than diminished. It was during these feverish times that Vallejo wrote his magnificent Poemas Humanos and the poems of España, aparta de mí este cáliz.

In March 1938 Vallejo became gravely sick. He died in a Paris hospital on the 15th of April. The doctors gave as the cause of his death intestinal infection. Vallejo's wife believed it was a recurrence of the malaria that had struck him in his youth. On his deathbed, he dictated the following words to Georgette: Whatever may be the cause I have to defend before God, beyond death I have a defender: God.'

Vallejo's poetry is essentially disruptive or disjunctive. This has been interestingly explicated by a recent Vallejo translator, Rebecca Seiferle, in terms of the collision of the two cosmogonies Vallejo inherited through his grandparents: the Western Christianity of his grandfathers and the Incan or Quechuan of his grandmothers. For the Quechuas (the main body of Indians ruled by the Incans), the family and the extended family or clan or commune of the ayllu was the cornerstone of society. The Quechua was born and died within the ayllu. He or she had no identity, no meaning, outside it. So organised, so socialised was Incan society, that not even the Incan nobility, not to speak of their Indian serfs like the Quechuas, were permitted the development or indulgence of individuality. That intensely socialised nature of the Indians survived the Spaniards. Their very existence depended on it.

As late as the 1950s in Peru, the travel-writer George Woodcock could write of the ayllu: 'Many of these Indians [of the Andean sierra] were members of villages still organised on the ayllu system which was already old when the Inca dynasty began. Under this system the land belongs to a commune (or ayllu), and it is redivided regularly so that each adult in the village gets his fair portion, while many tasks like house-building for newly-married couples are shared by the group. The ayllus are most self-supporting; they grow food primarily for their own consumption, with the potato as the basis on their farming, and they weave their cloth from wool produced by their own sheep ... There are nearly five thousand such communes in Peru alone.'

In his large family, Vallejo doubtless felt this deeply rooted sense of community, particularly in his relationship with his mother. That world, however, with its complex and complete interdependence, ultimately fell victim, at least in its social organisation, to the sword-like thrusting individualism of Western culture, though not so much that which was embodied in the conquistadors (who, after all, came from a Spain still possessed of medieval integratedness), as in the liberalismo of the 19th century. Vallejo's half-caste status (a cholo), his Western Education, his absorption of Spanish language and literature, put him in a difficult position. No doubt thinking of the Spanish hacendados and their Indian workers, Vallejo once said: 'On this side I suffer. On that side I suffer.' Not only does the seemingly chaotic imagery of Vallejo's poetry reflect the collision, or register the disjuncture, of these two worlds, but, more importantly, Vallejo subverts the very meaning of Western language, in this case, Spanish, by fracturing it, syntactically and lexicographically, with the weight of an alien cosmogony.

Vallejo's great literary legacy is undoubtedly Trilce, his book of 1922. It is a strange book, as strange as its title which has a memorable story attached to it. The original title of the book was Cráneos de Bronce ('Bronze Skulls') and it was Vallejo's intention to have the book printed at his own expense, using the nom de plume César Perú, in the manner of Anatole France. This did not please his friends, however, who poked fun at him. In consequence, Vallejo had a change of mind and decided to use his own name. But the first pages of the book were already printed and Vallejo had not the money (tres libras) to change the name. His friend Espejo relates what happened: Vallejo felt mortified. Several times he repeated words and deforming them, tress, trisss, trieesss, tril, trilssss. He stammered and in the lisp came out trilsssce ... trilce? trilce? He hesitated for a moment, then exclaimed: "OK. I'll use my own name but the book will be called Trilce."'