Books: The Crystal Frontier: Carlos Fuentes Bloomsbury pounds 16.99 Heading South, Looking North Sceptre pounds 16.99: A river with two names

CARLOS Fuentes and Ariel Dorfman were pioneering and formative writers of the Latin American literary boom of the Sixties and Seventies. Fuentes's Terra Nostra and Dorfman's How to Read Donald Duck (co-written with Armand Mattelart) were seminal examples of a genre typical of that period but which each writer interpreted in his own way.

Terra Nostra fused a sense of place and history, committing "literary parricide" against the European modernism of a previous cultural generation, and exploring that much-abused term "magical realism", which is generally defined as the cultural clash between rural, often indigenous and ancient, tradition and the post-Conquest legacy.

In Donald Duck Dorfman was reacting less to the hispanic culture that injected the "Latin" into native America than to US cultural imperialism - something he was well-placed to judge, having been born in Argentina, raised in the US, and then, in the Seventies becoming a student, teacher, writer and member of Allende's socialist government, before being exiled back to the States. He's long been an academic considerably more beloved of that establishment there than either his fellow exiles or Chilean compatriots back home.

Fuentes suffers from something of the same problem. Born into a diplomatic family in the United States, he became Mexico's ambassador back to Europe (it was somehow typical that he witnessed the Prague Spring and May '68 but missed the student-led uprisings and the horrific Tlatelolco massacre in his own country that left such a political and cultural residue). As the ferocious literary and political opponent of the "old lion" Octavio Paz, Fuentes tends to be viewed by his compatriots, in the words of critic Gerry Martin, as a "literary professional on the North American model, an Entertainer who does it His Way, a literary star". Never loth to mix the personal with the international, he has also come in for repeated satirical comment for harnessing US film stars to his novels' themes - Jane Fonda in The Old Gringo, and Jean Seberg in Diana: The Goddess who Hunts Alone.

Latin American writers' own situation a propos their overweaning northern neighbour is reflected in the flood of books which often aim to subvert this relationship. Fuentes's latest work, The Crystal Frontier, is no exception, offering a series of fictional interludes with a complex cast of characters criss-crossing the Rio Bravo, called, from its north banks, the Rio Grande.

The link between these episodes is a frontier-hopping narrator on a Harley Davidson. Jose Francisco is "so weird, with his shoulder length hair, his cowboy hat, his silver crosses and medals and his rainbow-striped serape jacket". He is, he says, "divided into four parts. I'm not a Mexican. I'm not a gringo, I'm Chicano. I'm not a gringo in the USA and a Mexican in Mexico. I'm Chicano everywhere. I don't have to assimilate into anything. I have my own history."

These views are echoed in a different context by Miss Amy Dunbar in "Las Amigas", the most successful of the short stories which together compose this "novel". Here, her new maid's refusal to perform as is expected of a Mexican begins to wear away at the bitterness Miss Dunbar has accumulated over the years, holed up in the bunker of her white supremacist convictions. Other chapters, however, worryingly miss getting beyond the stereotype they intend to query. "Pain", for example, concerns a homosexual relationship between a Mexican student, who invents fantasies about his parents' wealth, for the benefit of his rich American boyfriend. He learns that even were his stories of his land-owning background true, he would still remain plain Juan, while his lover securely stays "Lord Jim". The pain and shame is Juan's while Jim bids farewell, to do "what the families of the rich professional class did in Seattle, where it was expected that a young doctor would marry and have children - things that would inspire respect and confidence".

If this account of homosexual love is sentimental and banal, heterosexual relationships veer from embarrassing to excruciating in this disappointing book. Try "her buttocks were larger than they seemed, her legs thinner, like a thrush's - oh, woman of tempestuous eyes, immobile little nose, and nervous nostrils through which night escapes from you, parted lips, moist, through which my tongue gets lost without finding coral reefs or stalactite caves or ruined Gothic vaults."

In the opening story, the impoverished heroine with her wealthy businessman lover could almost have stepped out of Catherine Cookson: Michelina "complemented places, making them more beautiful. A chorus of macho whistles always greeted her, even in the small Campazas airport. But when the lover boys saw who was with her, a respectful silence reigned."

Fuentes's lack of critical distance from such cliched couplings is counterpointed by italicised intermissions itemising the repeated rape of Mexico from the Conquest to the present. Much is lifted from earlier and better books, mainly Fuentes's own, when he chose the historical themes he treated with originality and control. This one, though the newest, has an oddly dated feel to it, perhaps epitomised by the narrator's desire to learn to identify himself as Chicano just as - outside the safe pages of a novel, out there in reality - a fresh generation is renouncing the term as being as suspect as Uncle Tom, declaring itself to be Latino.

Ariel Dorfman has more reason than most to be hung up on the question of national identity. His new work, Heading South, Looking North, is suggestive of a vast Jewish ancestry which has spent since Genesis questioning who they are and where they belong. We learn in great detail of Dorfman's East European origins, his parents' peregrinations and then his own, which read increasingly like those of a lost tribe rather than reflecting lived political experience. Dorfman, who was a member of Salvador Allende's Popular Unity government which was violently liquidated in Pinochet's CIA-backed military coup of September 1973, opens by truthfully telling us, "I should not be here to tell this story." He is here because he turned back at a police-manned road block, changing his mind about showing solidarity and sharing the tragic fate of his fellow government members, who were killed (often after torture) by the incoming military dictatorship that was to last 17 long and brutal years. Inevitably, he feels the guilt of the survivor, the consequence of which is a tendency to rationalisation.

What we, as readers, need to understand is the co-existence of history and memory, how we continually remake the past to fit our poetical and personal panoramas. I visited Santiago when Pinochet unexpectedly lost the referendum and a civilian president was voted in. I went to La Moneda, the presidential palace where Allende and his ministers met their end. The guards asked me my business and I answered that I wanted to see how the place looked now, ready for the inauguration of democracy. They assured me that the TV images of Hawker Hunters bombarding and destroying it in 1973 was "pure Communist propaganda", and that "the only bombs ever dropped there were tear gas". I had to recognise a new generation, teenagers who believed what they'd been told rather than the evidence of their eyes, despite the reconstructed buildings alongside those still pocked with bullet holes.

In Dorfman's book, an autobiography - which is as disappointing in its way as that of Fuentes - we get 17 chapters ambitiously "Dealing With the Discovery of Life ... Language... Death", which frustratingly fail to get to grips at all. It reads like the notes on a protracted psychoanalysis, but unfortunately the big issues are reflected onto an individual who never quite serves as the prism through which they can be elucidated. The detachment that comes from privately having made sense of the experience, having somehow packaged it away in this or that corner of his own psychology, repeatedly interrupts the story at what should be its most vital moments. We lose the bigger picture without getting the vignettes that would offer us a fresh insight. When what we need to grasp is the personal in the political, we get psychology masquerading as philosophy.

The issue of language, for example, is crucial across the Americas. Yet just as we're tantalised with a fascinating account of "a man who is shared by two equal languages and who has to come to believe that to tolerate differences and indeed embody them personally and collectively might be our only salvation as a species", we're flung back into the details of "getting over the trauma of my first banishment from the womb".

Fuentes and Dorfman have become enormously well-known internationally. Their reputations are genuine in as much as both men have made a valid contribution to a literary and historical tradition. Immensely advantaged by their international connections, they are often regarded as marginal, even derisory, in Latin America. Curiously, it seems that as male writers explore the "female domain" of interior and emotional worlds, their writing becomes self-conscious to the point of self-obsession and self- indulgence.

If you want authentic literary voices speaking of Latino borders, forget The Crystal Frontier. Though less well known in this country, the voices are there in prolific and varied abundance: Sandra Cisneros, Ana Castillo, Martin Espada, Alberto Rios, Augusta Dwyer. Chile offers us fewer alternatives, as writers increasingly turn from directly political subjects. Yet Heading South, Looking North, while ostensibly presenting a wider image of the ambiguous network of the Americas, in fact offers us little more than a single piece of a large and intriguing jigsaw.