Seventeen years ago, not much was known among mainstream U.S. travelers about the Jewish heritage of the countries that had just emerged from behind the Iron Curtain.
Cemeteries had been destroyed or forgotten, synagogues were collapsing and little information was available at the region's town halls or tourist centers about hundreds of years of Jewish history.
Now the fourth edition of Gruber's guidebook, "National Geographic Jewish Heritage Travel: A Guide to Eastern Europe," reveals a revolution in monument care and the return of Jewish culture -- or a least tributes to that culture -- in areas where it had long been dormant.
Researching the first guidebook, Gruber said she "could go to a town and they would mention a 17th century cathedral or 19th century palace, but nobody included anything Jewish."
Gruber, a JTA correspondent, said that among Jews and non-Jews in the United States and Europe, "there was an assumption that nothing had survived the Holocaust and there was very little desire to know that there were vestiges of the pre-Holocaust Jewish world."
How times have changed.
"I remember in 1990 looking at sites in Czechoslovakia, and we sort of recognized that if we saw a clump of dirt in a field and a broken wall it was probably a cemetery," said Gruber, who has residences in Budapest and near Rome. "Now all of these places are known and documented."
Jewish heritage travel has made it into the mainstream, according to Gruber, who has written two other books on the recent revival of Jewish culture in Central and Eastern Europe.
"It's extraordinary, and extraordinarily important, that National Geographic is now publishing" her new guidebook, she said. National Geographic is "recognized over all the world. It gives an imprimatur of importance to Jewish sites."
The book includes everything from directions to little-known heritage sites to addresses of Jewish communal institutions.
Insider anecdotes and hard-to-find information is presented for Poland, Lithuania, Ukraine, the Czech Republic, Slovakia, Hungary, Romania, Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Macedonia, Montenegro and Bulgaria.
The restoration of so many Jewish monuments in these countries is due to myriad factors -- generous help from the West, decent planning by local governments, renewed Jewish community pride, non-Jewish devotion to history and the realization that Jewish sites could attract tourism.
"The Czech Republic is where things have changed the most," Gruber said.
"Look at the synagogue at Ustek," said Gruber, who notes in her book that the 18th century synagogue, located on a scenic perch, was just a "pile of rubble" in the early 1990s.
"It's been restored in a fantastic way," she said. "In three other towns near Ustek the Jewish cemeteries were scenes of devastation. Now they are cleaned up, marked with monuments."
Throughout the Czech Republic there are exhibitions in restored synagogues, and n 2006 the country devoted an entire year to Jewish culture, staging art shows, concerts and theater productions.
What went on in the Czech Republic has gone on to some extent across Central and Eastern Europe, said Gruber, who also has written "Virtually Jewish: Reinventing Jewish Culture in Europe" and "Upon the Doorposts of Thy House: Jewish Life in East-Central Europe, Yesterday and Today."
The rebirth of Krakow's former Jewish district, Kazimierz, has not only led to the reclaiming of Jewish synagogues there but to a more general revival that has turned the neighborhood into a top night spot with Jewish-themed restaurants and trendy bars.
"There was only one cafe there when my book first came out," Gruber said.
She gave mixed reviews to monument care in the rest of Poland, but said there were plenty of sites that would impress tourists, such as Lesko in southeastern Poland.
"It has a beautiful synagogue that is a landmark of the town, it's an art gallery," Gruber said. "The cemetery has about 2,000 intricately decorated tombstones dating back to the 16th century."
Gruber also had high praise for the Holocaust monument at Belzec, where the Nazis murdered some 500,000 Jews from the Galicia region in 1942. The monument was erected in 2004 with the help of the American Jewish Committee.
"It's breathtaking and unbelievable," Gruber said of the monument, which features slag that appears like a field of ashes and iron letters spelling out the name of former Jewish shtetls in the region.
In Lithuania, Belarus, Ukraine and eastern Poland, surviving but little-known wooden synagogues have become Jewish attractions, Gruber noted.
"About a dozen wooden synagogues have been identified within the past decade, and are really worth seeing," she said.
Of the more ornate Jewish cemeteries, Gruber urges tourists not to miss those in Romania and Ukraine because of their "sheer architectural beauty."
There is a small but vocal living Jewish presence in the region, and Gruber points out that has also undergone a revival.
For example, Prague's Jewish community has only 1,500 registered Jews, but "a tourist can now go to five or six services on Shabbat," Gruber noted.
That contrasts with the communities' moribund state during the communist era, when actively participating in religious life could lead to persecution by the secret police.
Gruber acknowledged that some people have an image of the former Eastern bloc as teeming with anti-Semitism, an image she seeks to dispel. Gruber notes a tremendous sea change among non-Jews -- not just toward Jews but toward foreigners in general, in countries where xenophobia once was prevalent.
In Luboml, Ukraine, Gruber met a local young historian obsessed with Jewish history, as is often the case for historians reclaiming their countries' past after communism made Jewish topics more or less forbidden.
"There had been a Jewish distillery; he gave me the labels of bottles to take home," she said. "You meet people like that all over the place. Of course you sometimes meet people who are awful, but that's true wherever you go."