When I saw the pile of shoes pictured in a newspaper I did not link it to the death toll in Lebanon. Instead it reminded me of a scene, described to me by an Iranian political prisoner in 1995.

In 1989 the Islamic government of Iran was afraid it might lose the war with Iraq and worried that increasing unrest in the country could lead to the overthrow of the regime. It decided on a purge of political prisoners, massacring 15,000 in accordance with a fatwa issued by Ayatollah Khomeini.

This man had his worst fears confirmed when, peeping through a doorway at Gohardasht prison – a jail 20 miles west of Tehran, he spotted a pile of yellow and green plastic prison-issue sandals on the floor and craning his neck further round saw the corpses of 30 to 40 men hanging from an iron bar.

These were the shoes of dead people, some of them his former cellmates. Rumours had been circulating around the jail for weeks but nothing definite was known. Now he knew. This news was passed around the prison that night, using the steel blinds at the windows of the cells, which were constantly lit, to send out coded messages to other blocks, or by simply banging out warnings on the water pipes.

The mullahs were giving prisoners a choice: recant any allegiance to the Mojahedin, a political grouping with an armed movement in Iraq, recant any belief in socialism, and become good Shi'ite Muslims supporting the state, or face the consequences.

Until then nobody had dreamt that meant death. Many socialists had already told the mullahs to get stuffed, and been 'taken to the top floor'. The coded messages explained in detail what questions would be asked and how they should be answered.

The prisoner who witnessed this episode, Dr Reza Ghaffari – a former professor of economics at Tehran university, finally got out of prison in 1989 and escaped to Turkey and from there made his way to England.

He had spent seven years in prison in Iran, accused of being a member of a left-wing organisation. When he got to England he lived at a secret address under a number of pseudonyms. His life was still in danger. The Iranian secret police had already assassinated three Kurdish dissident leaders in Germany and were known to be roaming Europe.

He wrote about his experiences as best he could – he never recovered physically – and his book was published in Farsi, German and Turkish. It has yet to find an English publisher.

As I read Hiro's account of this same Islamic regime, replete with its benign comments from apparently civilised ministers, I had flashbacks to episodes in Reza Ghaffari's unpublished memoirs, scenes that still fill me with shock years later.

The emaciated man they had to pull out of the toilet after he died on the lavatory; the torture Ghaffari underwent at Commiteh Moshtarack in central Tehran (using cells from the Shah's era) that led to a heart attack within 24 hours of his arrest; the bloodied bodies propped against walls in overcrowded prisons such as Evin, Ghezel Hessar (Black Fortress) and Gohardasht that he saw as he came out of interrogations. The scene of horror, reminiscent of ones in Costa Gavra's film Missing, about the 1973 coup in Chile, when at Gohardasht he spotted guards shoving dozens of corpses covered in plastic sheeting into refrigerated meat lorries. Was Hiro talking about the same government?

Most of us feel reassured if we are told that the author of a book or an article in a newspaper or magazine is written by a specialist. This person is not a Johnny-come-lately, who bases his work on secondary sources and cut and paste. We expect to be told things that we didn't know and perhaps to be able to put some trust in the judgments he or she reaches, whether it is boxing, health or international politics. Hiro is certainly a specialist writer, who has written a number of good books about the Middle East over the last 25 years, and the reader will certainly learn many useful things. But the fact remains that this one should be read with caution.

The difficulty with specialist writers like Hiro is that they tend to hoard contacts, especially those in high places, because that is where they can obtain their most authoritative information. The relationship is instrumental. The problem, of course, is that the contact, especially if he or she is an important figure in the national life of a country, is also encouraging the relationship for instrumental reasons. The contact wishes to put the best gloss on the actions of his or her government or company.

The difficulty arises if a source is linked with the unsavoury. What to do? Interrogate? Shine a light into those dark corners? Better to tiptoe around with code words like 'ruthless' and leave it at that. If the specialist starts going down the other road his best contacts will freeze him out. The minister will 'not be available'.

The specialist might send out a few coded messages (as Hiro does in Iran Today) but the narrative is likely to be skewed. For instance, a tiny almost trivial example. He refers to Shirin Ebadi, a human rights lawyer and one-time judge who won the Nobel Peace Prize in October 2003, and notes how this was downplayed in official media coverage. He gives a synopsis of her career and mentions that she was arrested and briefly 'detained' after one investigation. But the whole benign truncated quality of this narrative distorts the enormity of what happened to Ebadi, who is not a socialist, not a Marxist, just a sort of courageous liberal 'good soul'. She was locked up in Evin (think Lubianka) in solitary confinement for 25 days, after a secret trial (but not one we would recognise, as the cleric in charge would act as police force, crown prosecutor and judge), before she was released. The whole performance was an exercise in intimidation reminiscent of some Stalinist show trial in the 1950s. The message, of course, was clear: you are not immune, next time will be worse.

This is not to say Iran Today is a write-off. Far from it. The chapter on the conditions that led to the nationalisation of the Abadan oil refinery, and the overthrow of Mohammed Mossadeq, for instance, is worth the price of the book in itself. Vivid, succinct, comprehensive. Ditto the chapter on 1930s and the influence of secularism and the Nazis. The coverage of the jockeying for position between popularly elected, if religiously vetted, MPs in the Majlis and the elected president on the one hand and the religious hierarchy on the other illustrates the fact that the Islamic regime is a hybrid form of dictatorship. The brief but illuminating synopsis of the career of Mahmoud Ahmadinejad, the president, illustrates the support that it can call on.

But in a sense this all makes it that much worse. Hiro is a good journalist. He knows what he is doing.

The truth is that Hiro has too many contacts among the high-ups and not enough among those that have been brutalised and murdered. The effect is to give his narrative a neutral quality that is an affront to its victims and the many thousands who continue the fight both in Iran and outside. (Some of the men who orchestrated the 1989 massacre became, for instance, leading officials. Mostafa Poormohadi was on the original death committee of three and is wanted by the authorities in Germany over the murder of the Kurdish dissidents. He became a Home Office minister. Said Mortazavi, implicated in the death of an Iranian photographer, became the Islamic Republic's Human Rights commissioner at the United Nations. Neither earns a place in Hiro's book.)

At a time when Iran is correctly standing up for itself against American imperialism, it is crucial not to be gulled yet again (as many were in 1979) into turning a blind eye to the viciously anti-women, anti-secular, anti-liberal, anti-trade unionist, anti-socialist, anti-national minorities, and anti-religious minorities nature of the regime.

In the 30 years since this theocracy of thugs came into power the death toll of political opponents (socialists, liberals, trade unionists, members of religious minorities and so on) is put at 50,000. Some might say that the regime has mellowed over the years, but there is little evidence of that. Reza Ghaffari, for instance, has been a thorn in its side since he got out of prison, analysing the political and economic situation in Iran and talking about his experiences on radio, television and in the press, mostly in the US. The regime didn’t like it and made its feelings clear to a member of his family. Five years ago he had to leave his home in the UK and go into hiding for a number of months under the protection of the British security service, which was satisfied that his life was in danger.

Stephen Kinzer is a veteran journalist, a correspondent on The New York Times, and All The Shah's Men recaps the events surrounding the overthrow of Mohammad Mossadegh and the installation of the shah in 1953. The subtitle is An American Coup and the roots of Middle East terror.

The full details of the coup, which was organised and financed by the Dulles brothers (the CIA and the State Department) are now a matter of public record. The name of the exercise was Operation Ajax. In 2000 the then Secretary of State, Madeleine Albright, on behalf of the US government, offered a sort of apology for American actions. It read: “In 1953 the United States played a significant role in orchestrating the overthrow of Iran's popular prime minister Mohammad Mossadegh. The Eisenhower administration believed its actions were justified for strategic reasons. But the coup was clearly a setback for Iran's political development. And it is easy to see now why many Iranians continue to resent this intervention by Americans in their internal affairs.”

Kinzer delves into the nuts and bolts of how the coup was organised and who was involved. Britain, of course, was up to its neck in it because of the threat to the oil refinery at Abadan, which was a colonial outpost with swimming pools and tennis courts for the British administrators and slum housing for tens of thousands of Iranian workers. Buses, cinemas and other amenities were reserved for the British. Herbert Morrison was the inexperienced Foreign Secretary after Ernest Bevin had retired for health reasons. As Kinzer puts it: “He considered the challenge from Iran a simple matter of ignorant natives rebelling against the forces of civilisation.” Morrison made it clear that the UK would intervene militarily and started manoeuvres in 1951. The Truman administration looked askance at these 19th-century bullyboy tactics but with the election of Eisenhower and the advent of the Dulles brothers the gloves came off as the Iranians became another Cold War casualty. It's all enough to make you weep.

–  Michael Wagstaff