FOR a writer at a literary festival there is only one thing more terrifying than an empty room: a full one. The rows of intelligent, expectant faces trigger a frisson of fear and joy. Fear, because what if we make a fool of ourselves? And joy, because somebody loves us enough to come and listen.

Still, it's always been a puzzle why writers are assumed to be skilled public speakers. Writing, after all, is a solitary, introverted profession. We sit, hunched over our laptops, tapping away, each key stroke another step on an inner journey that will eventually be presented to the public. Public speaking is for politicians, full of their own importance.

But writing a book also demands considerable self-belief. And perhaps some (mild) ego-mania. So it is testimony to the power of words that, even in the era of the sound-bite culture, literary festivals are thriving. Perhaps it is a reaction to the dumbing down of cultural life. Readers not only like to read books, they love to talk about them, and meet their authors.

In Britain there are dozens of literary festivals held every year, ranging from small community events to the Edinburgh International Book Festival, the largest. In Edinburgh, especially, the life of the mind is thriving, rooted in its literary heritage. The city's imposing Georgian terraces, of well preserved grey stone, may appear austere.

But perhaps it is the very severity of those sober walls that encourages flights of fancy. Edinburgh is proud of its writers: current luminaries include J.K. Rowling, of Harry Potter fame, and Ian Rankin, author of the Rebus detective series. They are in good company: Robert Louis Stevenson, Sir Walter Scott and Arthur Conan Doyle, creator of Sherlock Holmes, all lived here.

This year's book festival lasts for 17 days, from August 11th to 27th, and includes more than 700 events, with more than 600 authors from 40 countries. Including me.

I was thrilled to be asked to appear twice, reflecting the fact that I have recently published two very different books. "City of Oranges: Arabs and Jews in Jaffa", is a new take on an oft-written about issue, Israel and Palestine. It recounts the true life stories of six families in Jaffa, three Arab and three Jewish. "Complicity with Evil: the United Nations in the Age of Modern Genocide" is an investigation into the United Nations' failure to stop the genocides in Bosnia, Rwanda and Darfur.

Israel and Palestine always arouse furious passions, so I expected some probing questions. In fact the liveliest exchanges at my first event, about Jews and Arabs in the Middle East, were with my fellow on-stage author, David Pratt, author of "Intifada". We found much to agree on, including a shared admiration for the Israeli writer Amos Oz and the need to give a voice to the Israeli left and peace camp. And then we did not agree at all.

Mr Pratt was expounding on what he described as "the Jewish lobby" in the United States, which, he claimed, was manipulating the White House. Alarm bells rang in my head, for there is no Jewish lobby. The Jewish community—rather, communities—in the United States speaks with different voices, on Israel, on every topic. AIPAC, the American Israel Public Affairs Committee, is certainly influential, but AIPAC is not a Jewish lobby, it is an ardently pro-Israel one. To suggest, I said, that Jews somehow control the United States government, is to use an anti-Semitic stereotype.

Boom! Mr Pratt exploded in righteous indignation. I was waiting to see how long it took before someone accused me of anti-Semitism, it always happens when I criticise Israel, he proclaimed, which is itself a kind of stereotype. I disagreed, again. It is not anti-Semitic to criticise Israel. Nor had I said that it was. Mr Pratt backtracked. He had meant to say "the Zionist lobby". A small but crucial, difference. And apt testimony to the power of even a single word.

The next day I read from "Complicity With Evil". It is a depressing business outlining the United Nations' failures, and still the slaughter continues in Darfur. The best question, as usual, was the simplest: "What can I do?", asked one man. Make politicians know that there are votes in human rights, set up a Darfur support group, join Amnesty International and the United Nations Association (UNA), I advised.

I thought again about that last recommendation, when the head of the local UNA, a doughty Scottish matron, proclaimed that many of the world's problems flowed from the fact that, as she put it, a certain permanent member of the Security Council refused to pressurise its Middle East ally to do what the United Nations demanded. I am talking about the United States and Israel, she proclaimed dramatically, although this was hardly unexpected, or indeed accurate. The activists' obsession with Israel remains a mystery, though I'm not sure you'd have to be a Sherlock Holmes to solve it.