I’ve never seen anything like it. Rivers of people were cascading down the aisles of a book fair. Thousands of readers were carrying bags upon bags of books. This was the International Belgrade Book Fair, held once a year in Belgrade, Serbia. I was an invited guest of Admiral Books, there to promote and sign copies of a book of mine, Einstein’s Daughter, which had just been published in Serbian translation.

The fair’s mission is similar to that of the book fairs in London or Frankfurt or Berlin. Like them, it was created to enable publishers, foreign rights editors, authors, booksellers, librarians, distributors, and multimedia companies to meet and establish contacts and make deals. But in some ways Serbia’s book fair differs from the others. In Serbia, publishing houses own most of the bookstore chains. And, more striking, the Serbian public regards this fair as a national event. Indeed, students from all over the country are driven for hours to attend. A waiter at the hotel where I was staying told me that “attending the fair is a declaration of national honor.”

“Over time,” said Ivana Stefanovic, a renowned Serbian composer and writer, “the fair has grown as an event and has educated generations of Serbs. Despite some ups and downs, this event represents yet another Serbian paradox. Even when other things aren’t going well, the fair continues to thrive and develop.”

I came close to embarrassing myself. I had not understood that Serbia was such an earnest book-reading country, and I had not reread Einstein’s Daughter since it was published in 1999. My plan had been to fly to Rome first, allowing for a nine-hour stopover on the way to Belgrade. I was to have lunch with an old friend and visit my Italian publisher at Europa Editions. At the last minute both appointments had to cancelled. Instead, I read. I finished the book—and was later greatly relieved that I had. The questions asked by the Serbian media were complicated, intelligent, and demanding of my memory.

Serbia is a landlocked country of seven million people. People on the street look like those in any other European country, or in America. But the feeling in the air was unfamiliar to me. Perhaps this was due to Serbia’s insular nature; the country has been ostracized by world opinion for its roles in the Balkan war of the 1990s and in World War II. The country, sadly, does have a habit of making enemies. However, things are changing. The European Union announced in March 2012 that Serbia had become an official candidate to join the EU. Many people don’t think it’s going to happen. They think that the country is still too internally divided—too torn by ancient ethnic hatreds.

I had experienced Serbia several times before, while working on my book—twice when the country was at war, and once when there was promise in the air. In 1992, I began researching Albert Einstein’s first wife, Mileva Maric, and her family and friends. Mileva was a Serb, born in the tiny village of Titel, near the River Tisa. When she and Albert first met they began a passionate affair. Mileva became pregnant. She went home to give birth to their child. Ninety-one years later, I went looking for what had happened to the missing child, Lieserl.

Einstein’s Daughter: The Search for Lieserl was published in 1999 by Riverhead Books, a division of Penguin Putnam, Inc. A couple of months later a German edition was published by Der List Verlag, Munich.

Thirteen years later, I received an email from Andrijana Cvetković, an editor at Admiral Books in Belgrade. She asked if her firm could buy the rights to the Einstein book and translate it into the Serbian language. The deal was made. Although many chapters of my book took place in Serbia, it had never occurred to me to ask my agent to try to sell it there. More important, it had never occurred to me that books I had written many years ago could have their own lives. Indeed, having done a year of readings and promotional events after the book’s publication, I was relieved to be done with Mr. Einstein and his disheveled life. But Serbia and its people continued to interest me.

While I was writing the book, I came to understand that Serbian society is private and intensely loyal. It takes months to cultivate friendship, sometimes years to earn the right to call someone by his or her first name. One must demonstrate absolute loyalty to be taken into another’s confidence. From the beginning of my research in Serbia, I respected the responsibility that was conferred upon me when a truth was shared. And because I was seeking the truth about Albert Einstein’s lost daughter, I quickly learned the rules, and the Serbian citizens whom I interviewed welcomed and encouraged me.

The last time I had landed at the Belgrade Nikola Tesla Airport, the airport had been in shambles because of the war. Now it had been renovated. Smoking in Serbia had historically been practically a national pastime, so I was surprised that the expected and overwhelming smell of cigarette smoke was gone.

Three people met me: Andrijana Cvetković; one of my two translators, Margita Rapajić, a part owner of Admiral Books; and George Djordje, who was our driver and who is also a well-known photographer. Andrijana (who quickly became “Ana” to me because I kept fumbling the pronunciation of her name) escorted me throughout the week. Her English was excellent; like almost all Serbian students, she had been studying it since she began her primary schooling.

It was ten at night when I arrived in Belgrade. Ana informed me of the plans for my visit. I was scheduled to appear on all the major television and radio shows, and had appointments for numerous interviews with newspapers and magazines. I had never done such a concentrated set of interviews. My hosts soon began calling me their “literary rock star”!

I stayed at the Hotel Moskva on Terazije Square. This is a historic area at the confluence of the Danube and Sava Rivers. The hotel had been built in 1904, in the Russian Art Nouveau style; it was green and beige and quite pretty from the outside. This was a return visit for me; I had stayed at the hotel in 1992 during the war. Then, the rooms had been dingy—the windows unwashed, the light bulbs of the lowest candlepower. Sinister-looking men had wandered the halls, often with their hands on their holsters. Soldiers had lingered in the lobby with machine guns hanging from their shoulders. Indeed, I had seen people taken off the street and shoved into cars at gunpoint.

Today, the hotel has changed considerably. It is clean. Modern. No soldiers standing guard. No guns (at least that I could see). But back in 1992, crazily enough, I could get the International Herald Tribune. Now, in 2012, I could buy only a photocopy of the newspaper, with two staples holding it together at the spine.

The next morning, Ana and I drove to meet Goran Skrobonja, the man who had been the translator for my book, and who would also serve as my translator for the media. As we were driving, I noticed that the bombed-out buildings in downtown were still unrepaired.

“Are the buildings being left as a reminder of the war?” I asked.

“No, the government can’t repair them,” Ana said. “There’s no revenue. We’re in a terrible financial situation.”

“Is there still serious anti-American sentiment because of the bombings?” I asked.

“Yes, sadly,” she said. “But we are always connected by literature.” She smiled. “Because we are an insular country, books are our lifeline to the rest of the world. We will always find enough money to buy books!”

Later, I met the publisher of Admiral Books, Zoran Rapajić. “You are the first foreign author that our company has invited as a guest to our fair,” he said. “Your being here is a priceless experience for us.”

I felt there was something different in the air—something different from my other trips. Then I realized: it was the books. Books, books, and more books. The book fair is the largest cultural event in Serbia—indeed, in southeastern Europe. The hotels were bustling with foreign publishers. Fancy restaurants were filled to capacity. Banners about books festooned the streets.

Vida Ognjenovic is the Serbian ambassador to Denmark. She’s also a well-known fiction writer and playwright. I met her many years ago when I was doing the Einstein research. I remembered her telling me that during the bombing she slept in her bathtub because there were no windows in the bathroom and she could keep her light on and read as late as she liked. It wasn’t that the government had declared a blackout; it was Vida’s landlord who remembered World War II and wasn’t going to take a chance.

I asked Vida what she thought about the book fair. “I could say that on behalf of my fellow writers in Serbia, there is a real festivity, a kind of magic that pervades the fair. We sign and exchange books, attend or participate in each other’s readings, give interviews, meet our translators and reviewers (even those we otherwise do not care to meet!).

“Books around us, books on the tables in front of us, books in bags, books in our conversations, books on our minds. It gives us the illusion that not so many bookstores have been closed down in the last two years.”

Željko Ožegović is the president of the Belgrade Book Fair board. I asked him how the fair was different from the other international fairs. “We plan this fair,” he said, “to follow the Frankfurt Book Fair. Frankfurt is where our main job of copyright buying and selling is done. In Belgrade the educational and cultural mission of the fair is carried out. The book fair is the communication point between publishers and the media, and certainly between publishers and the general public.

“I know this is hard to believe, and it depends on the country’s economy in the particular year, but we sell anywhere from 500,000 to a million books during each book fair!

“This year there were 889 participants, including publishers from Hungary, Slovakia, Greece, Austria, China, Russia, Byelorussia, Iran, Croatia, Bulgaria, Bosnia and Herzegovina, Montenegro, Angola, Germany, the Netherlands, Italy, Spain, Japan, and Portugal.”

The United States was not represented. Why? Perhaps it’s because our writers are not well-enough informed about smaller fairs. I think that we are geared toward big-money sales, forgetting that smaller fairs can be both exciting and important to our careers. Yes, Serbia is considered a small market. However, it has a vibrant, bustling readership, curious about the rest of the world. Serbia wants to break through its isolation.

For five afternoons, I signed books at the fair. On the last afternoon, Ana and I were in a taxi riding out to the fairgrounds. The driver was chatting with Ana and she was translating for me.

“Why are you going to the book fair?” asked the driver.

Ana explained that I was an author and that she was an editor whose firm had translated my English-language book into Serbian.

“What’s the book?” asked the driver, and Ana told him “Einstein’s Daughter.

“No,” said the driver.

“Yes,” said Ana, who I could tell was a bit miffed at his dismissive tone of voice.

“Well.” he asked. “Is this it?” And he was laughing as he held up my book, which had been lying beside him on the front seat.

“It’s a great book,” he said. “Will you sign it for me?”