The Battle of Algiers, Gillo Pontecorvo’s 1966 cinematic masterpiece, has powerfully shaped western perceptions of Algeria. The film (which features scenes of Algerian freedom fighters being electrocuted by French torturers to the sound of Bach’s musical epiphanies) incarnates the semi-religious national myth that the victorious National Liberation Front (FLN) imposed on Algeria after driving out the French in 1962. The winners in the bloodiest of French colonial wars were presented not just as victims, but as martyrs, almost as saints.

The gulf between this official myth (which, to this day, sustains a highly unsaintly, corrupt and brutal ruling elite) and the terrible realities experienced by most Algerians for the past four decades, is at the heart of this stunningly important book. Martin Evans and John Phillips have an enviable grasp of the complexities of Algerian identities and the country’s often opaque high politics and are alive to the multiple ironies of Algerian history. Even as the hard-faced former guerrilla colonels who ruled Algeria from 1962 onwards were feted as the darlings of the nonaligned Third World, they ruined a country rich in oil and gas by imposing a nationalising socialism that masked their promiscuous thievery.

By the late 1980s, Algeria was so bankrupt it had to undergo liberalising reforms that made matters worse for anyone not in the inner circle. In 1988, there was an explosion of discontent by young unemployed urban males, who had developed their own culture of football hooliganism, drink and drugs, and rai – a fusion of North African folk music with the nihilistic political messages of rap, reggae and punk. Algeria’s military rulers (who alighted on Islamism as a substitute for a discredited socialism) discovered that they could not contain its more radical manifestations, which included populist preachers intent on channelling the rage of the youthful dispossessed against western modernity. The Levi 501s could be combined with a Koran and a Kalashnikov.

After licensing the Islamic Salvation Front party (FIS) in 1989, Algeria’s rulers, supported by feminists and the diminished fran-cophone middle class, belatedly realised that the radical Islamist view of democracy was “one man, one vote, one time”, although they were no paragons in this respect themselves since the elections called in 1991 were the first since independence.

In response to clear Islamist victories in the first round of the elections, the military launched a preemptive putsch. Neither side gave any quarter. Victims of the armed Islamists included journalists and novelists, as well as those rash enough to have a satellite tuned to “pornographic” French television: their severed heads were liable to end up in the disconnected dishes. The most radical terrorists declared the population “apostates”, which licensed a campaign of rape and throat-slitting against entire villages.

The regime’s response was to “make fear change sides”. Prisoners were welcomed to the prison at Blida, where the blowtorch ruled, with the words: “Here we do not know God or Amnesty International: you talk or you die.” General Smain Lamari, the head of the security police, who died last October, contemplated the necessity of killing “3m people” to eradicate Islamism. As several security-police defectors cited in the book have testified, it was far from clear who was killing whom, since some massacres carried out by Islamists were the disguised handiwork of the army and police. An estimated 200,000 people perished in this war, although in western eyes the atrocities were eclipsed by belated revelations from elderly French torturers about their own dirty war four decades before.

In the present day, the war on terror has ensured a flow of arms and funds to a friendly regime that the CIA regards as a valuable window into Islamic radicalism in both the Maghreb and neighbouring states such as Mali and Mauretania. Algeria is a huge source of oil and natural gas, too, for China, Europe and America, none of which will wish to see the departure of President Abdelaziz Bouteflika. Although the authors do not spell out the wider implications of their study, they have identified a crucial difficulty for the West, one that extends far beyond the borders of Algeria.

Do we continue to mouth homilies about democracy, knowing full well that it may result in the Islamists’ “one man, one vote, one time”, or do we connive in the repressions of reliable dictators, even though these also affect the cosmopolitan liberal middle class, who, in an ideal world, we would all like to see in power? Or do we take a chance that the Islamists’ support is essentially an inch deep, mile-wide protest vote that will not result in the imposition of sharia and the dissolution of Algeria (or, come to think of it, Pakistan) into a caliphate? This outstanding book gives materials aplenty to begin answering those questions.

ALGERIA: Anger of the Dispossessed

by Martin Evans and John Phillips (Yale £19.99 pp352)

Available at the Sunday Times Books First price of £17.99 (inc p&p) on 0870 165 8585

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