Sensitive to all that is physically present

In 2004, the Chilean President wrote that the centennial of Pablo Neruda's birth was a cause for "celebration not just for one country, but for a continent, a world". The sentiment seems overoptimistic.

Argentina's Jorge Luis Borges, with his small scale and sophisticated irony, is more in tune with current times than the broad brush and heart-felt passion of Chile's Nobel prizewinning poet. Yet Adam Feinstein's exhaustive and indispensable biography, the first in English with full scholarly apparatus, shows we still have much to learn from a life and a body of work whose breadth can barely be contained by these 500 pages.

A Passion for Life often reads like an adventure story. Even familiar episodes, such as Neruda's daring flight across the Andes on horseback, are enlivened by well-chosen details, as when one witness compared the disguised plump poet to a "bearded sack of potatoes in a saddle". And Feinstein reminds us of a time, not so long ago, when a poet could achieve the kind of international fame now reserved for movie stars and pop idols.

Neruda, who was born to a modest provincial family in 1904, was still quite young (and had not yet adopted his nom de plume ) when he headed for the capital, Santiago. Feinstein describes his dandyish appearance at the time: "black suit, wide-brimmed hat, and striking black cape". Beginning a pattern of migration, he would soon set off again for minor diplomatic posts in Asia. Clearly, there were compensations for Neruda's exile: we are told of his affection for his pet mongoose and his faithful manservant (later, an undomesticated badger makes a memorable appearance).

The early collection Twenty Love Poems made Neruda a celebrity by the age of 23, but it was the experience of the Spanish Civil War and the murder of his friend Federico Garcia Lorca that confirmed his commitment to leftist politics. Neruda later wrote that his greatest achievement was the saving of 2,000 Spanish exiles, whom he brought to Chile in a fishing boat. By the 1940s, Neruda was elected a Communist senator in Chile, only to be forced into hiding by the dictator Gabriel González Videla. Feinstein confirms that this was productive: Neruda wrote most of his epic Canto General around this time.

In Feinstein's later chapters, the biography risks collapsing into an itinerary, as the poet skips from the fleshpots of Capri and Venice (there is a memorable gondola chase) to Stalin's Soviet Union and Mao's China.

Neruda's last years brought renewed acclaim (the Nobel prize in 1971) and a tragic death (just days after the 1973 coup that swept Augusto Pinochet's dictatorship to power).

Feinstein interweaves this colourful narrative with substantial extracts from the poetry in his own excellent versions, which avoid the twin traps of Neruda translations into English: pomposity and banality. And while Neruda once called himself "The Invisible Man", it is Feinstein who deserves the description.

Modestly marshalling a huge range of sources (including some in Russian and Chinese), Feinstein focuses on the two big themes of sex and politics.

Neruda, who married three times and was incorrigibly unfaithful (although he seems to have insisted on the tenuous distinction between fidelity and loyalty), proposed marriage to two women simultaneously, "juggled" a wife and lover through the course of a lengthy European tour and, late in life, took up with the young niece of his last wife.

His own unreliable memoirs make for uncomfortable reading today. A first sexual encounter is with an anonymous, indeed faceless, peasant woman.

Later, the improbably named "Josie Bliss" is described as a "Burmese panther". So numerous and willing are the conquests that even global fame seems insufficient lubricant for the unprepossessing poet, who compared his appearance to a turkey.

Reserving judgment, Feinstein gives us two versions of one sexual feat: in the first, Neruda tells of a willing tryst in a bell tower; in the second the woman in question claims that she called loudly to be rescued from Neruda's unwelcome advances. Feinstein suggests generously that in Neruda's poetry, "the object holds power over the artist". The problem would seem to be that there were, by Neruda's own account, so many objects and they were so thoroughly objectified.

Feinstein also proposes that "love sheltered Neruda from political disillusionment". Yet, quietly, he insists on the poet's refusal to denounce Stalinism over the course of several decades. Andre Gide had blown the whistle on the Soviet Union as early as 1936; Neruda could not bring himself to criticise it until as late as the invasion of Czechoslovakia in 1968. Neruda staunchly defended his own shift from lyric to political poetry ("You will ask: and where are the lilacs?") and lionised the "Great Leader" ("His bedroom light is turned off late/ The world and his country allow him no rest"). Yet Neruda's "Stalinist sickness" (the phrase is that of long-time antagonist Octavio Paz) does not diminish his heroism in confronting fascism, whether in the person of Gonz lez Videla, who ordered his arrest, or Pinochet, who harassed him on his deathbed.

Feinstein's keen attention to Neruda's sexual and political contradictions does not disguise his passionate empathy with his subject. Feinstein soft-pedals the psychology, refusing to speculate that, say, the fact that Neruda never knew his mother might have influenced his lifelong Don Juanism. The nearest he comes to an overall theory uniting life and work is that Neruda's Marxism, his materialist politics, might be linked to his acute poetic sensitivity to all that is "physically present".

Certainly the biography is peppered with Neruda's own unforgettable images, from the southern rain that falls like "long glass needles" to a pair of socks described as "two woollen fish". His beloved Chile is memorably imaged as a "long petal/ of sea and wine and snow". Several times, Feinstein compares Sartre's nausea unfavourably with Neruda's lust for life. Ultimately, in this exemplary biography, it is Neruda's sheer joie de vivre that wins through, proving more than a match for existential malaise.

Paul Julian Smith is professor of Spanish, Cambridge University.