Kanan Makiya exposed the operation of Saddam Hussein and his inner circle to the outside world in the 1990s. Now he turns to the Dome of the Rock, throwing a new light on age-old questions of tradition, religion and tolerance

Still sipping my latte, I reach idly for the newspaper and spread it on the table in front of me. En route to an interview with an Iraqi architect and film-maker who has written a novel about seventh-century Jerusalem, one ought to be up to scratch on the latest dispatches from the Middle East.

The picture stuns me into stillness. Heat and dust shimmering in shades of grey and olive green. A row of fuzzy men, some in uniform, some aiming cameras, behind a police line. And in the foreground, an image of which, at first, the eye cannot make sense. A body? A machine. "Suspected Palestinian suicide-bomber dragged away by Israeli bomb-disposal robot", the heading explains.

Not a body, then. Alive - if that's the right word. Inside, there's a picture of an Israeli man whose wife was killed by just such a suicide bomber a few days previously, weeping, supported by his two sons.

Dazed, I ask Kanan Makiya when I meet him if he has seen the newspaper. "I saw it," he says, quietly. "It's almost as though . . ." He makes a gesture, half shrug, half apology. "They say conflicts in a family are the worst kind. At the moment it reminds me of that Sartre play, No Exit. There's no way out - and this is going to go on until there are more reasonable leaders on both sides. The Israeli logic on this is utterly deadly. It's going nowhere, and will only bring more violence. And the Palestinians no longer see the Israelis as anything but targets for their rage. Now it has reached a point where they have too many volunteers for these insane acts of suicide bombing: kids, lining up." His book, he adds hurriedly, is not an attempt to fix the situation. "It's just another way of looking at it."

Born in Baghdad to an Iraqi father and an English mother, Makiya can no longer enter his native Iraq - not even the Kurdish north - because of his connections to the Iraqi opposition. His non-fiction books, The Republic of Fear and Politics of Modern Iraq, exposed the workings of Saddam Hussein's inner circle to the eyes of the world, as did his highly-praised 1992 TV documentary, Saddam's Killing Fields. He won an award for Cruelty and Silence: War, Tyranny, Uprising and the Arab World, his 1993 analysis of the wider issues affecting the Middle East.

But his new book, The Rock, is closer to poetry than to politics. A leisurely meditation on the building of the Dome of the Rock, it traces the history of one of the world's most sacred - and most disputed - sites; a Muslim monument built by Christian craftsmen to celebrate a Jewish holy place.

How did Makiya become interested in such a topic? He smiles. "The fact was, I had to run away from the modern police," he says. "All my previous books were about the modern police - and about Iraq in particular. I needed to write about something that was a happier moment. And," he adds, his eyes twinkling, "to go back a long time." The Rock, was planned, initially, as a non-fiction work.

"I wanted to travel through the stories I had unearthed and use myself as a narrator - but it didn't work, and the reason, I think, is that the central character of my book is the Rock itself. I couldn't make that rock come alive; I needed a character to give it voice." He found that character in the historical personage of Ka'b al Ahbar, a Jew who converted to Islam in the seventh century and accompanied the first Muslim Caliph, Umar, during his conquest of Jerusalem. "Ka'b is a strange, elusive figure," says Makiya.

"Of course we have nothing written by him - written texts exist only from the eighth century onwards - but he is the source of all the Judaic-type material in Muslim law. The way the histories are written, you get 'So and so says according to so and so', right down the chain, 'that such a thing is true' - and the very last link on that chain, when it's a story about the Rock or about Jerusalem, will be Ka'b al Ahbar."

As an architect, Makiya was drawn to the history of the extraordinary Dome of the Rock, built some 34 years after the conquest by the ninth Caliph, Abd al-Malik, as the first aesthetic monument of Islam and quite deliberately intended to rival the Christian Church of the Holy Sepulchre in beauty and scale. But what fascinated him was what he calls "the Jewish-Muslim nexus at the origins of Islam" - the shared stories, the shared beliefs, and the spirit of mutual tolerance which operated at the time of the conquest.

"One of the things that this conflict has done is to construct walls and prejudices between the two sides," he says. "Near the end of the book there's a picture of a coin that Abd al-Malik issued in the the year the building was inaugurated, 692. On one side it has the Arabic verse 'In the Name of God the Merciful, the Compassionate' and on the other side it has the Jewish menorah, the branched candlestick. Just imagine that today."

The book is a treasure-trove of arcane lore, scraps of poetry, religious quotations, gossipy details, architectural commentaries and frankly fictional inventions. The research is awesome - the "Sources" section is at least as fascinating as the main text, as are the notes on the illustrations which appear, captionless, at random throughout the book. It can be difficult for the reader to tell whether a given story, or detail, or even a passage of Scripture, is Jewish, Muslim or Christian in origin. Which, as Makiya, explains, is the whole point.

"The seeds of the book lie in my first visit to Jerusalem. It was October 1990; Saddam Hussein had invaded Kuwait and there were a lot of pro-Iraq demonstrations by Palestinians on the Temple Mount, so it was a big deal for an Iraqi to go." With the help of a British passport and a Palestinian archaeologist friend, he found himself in a city which, thanks to the shooting dead of 13 Palestinians who had been throwing stones at Israeli soldiers on the Wailing Wall, was eerily quiet.

"It was one of those beautiful sunny days with that very special Jerusalem light, the backdrop of the desert and this fantastic stone-clad mountain which goes back to Solomon's time, its walls coming down straight and sheer - and there, in the centre, on its own little podium, this wonderful golden dome. I noticed, on the ground, criss-crossing black streaks. And as I got closer I saw that each of the streaks culminated in a flowerpot with lush greenery in it. I was told that the streaks were blood, and that each of the pots represented a place where one of the 13 Palestinians had fallen and died. Their clothes were collected together - to this day, if you go into the Dome, you'll see their Reebok sneakers in a glass case. A few days later in the western part of the city, the Jewish part, there was a series of stabbings and a crazed Palestinian killed a woman. I decided to go and visit that site - and lo and behold, there were the same streaks, and the same plant pot. So it's that . . . I don't know what to call it. That common set of rituals.

"That's what I found very moving, and that's where the idea for the book came from." Reaction to The Rock has, among liberal Western critics, been largely favourable. It will shortly be published in Arabic, and Makiya is working on a Hebrew edition - both will doubtless elicit battling responses.

Meanwhile, his own battle continues; at his Washington-based Iraq Foundation, a team of researchers are busy with more than three million pages of official Iraqi police files, captured by the Kurds during the uprising that followed the Gulf War. "We're putting them online, and we're developing tools to search for information in them. This would, potentially, be used if charges of crimes against humanity are brought against Saddam Hussein's leadership." Happier moments are, it seems, going to be few and far between.

The Rock: a Tale of Seventh-Century Jerusalem, by Kanan Makiya, is published by Constable at £14.99 sterling in UK