These are rich prizes for tens of thousands of Jews worldwide who dedicate time, energy, and sometimes considerable amounts of money, to researching and documenting their family history.
Interest among Jews in tracing their roots emerged in the late 1970s, but it has been in the decade since the collapse of communism that Jewish genealogy has come into its own.
For the first time since before the Holocaust, the fall of the Iron Curtain opened up ancestral Eastern and Central European Jewish homelands to travel and research.
Conditions are still difficult in some places, but people now can physically walk in the footsteps of their ancestors, as well as consult local documents such as birth, marriage, death and census records that were long kept off-limits to outsiders.
At the same time, the growth of the Internet opened up vast new resources, enabling roots-seekers to tap into ever-expanding databases and keep in touch via e-mail with fellow researchers and contacts in Eastern Europe, including newfound family.
Last August, for example, more than 1,200 people, the biggest crowd ever, attended the 19th Annual Conference on Jewish Genealogy in New York -- and dozens more were turned away for lack of space.
In 1990, there were 39 Jewish genealogy societies worldwide. Today there are 75, with 8,000 registered members. They represent only a fraction of Jews who are interested in tracing their roots, however -- some 30,000 people alone are registered with a "family finder" service on the leading Jewish genealogy Web site, www.JewishGen.org.
"I got involved when people started to contact me by e-mail asking me to check information, to do some research," said Ladislau Gyemant, a Jewish and European history professor at Babes Bolyai University in Cluj, Romania, who carries out professional genealogical work in Romania and Hungary.
Jewish genealogist Miriam Weiner has been a major force in the movement. She negotiated agreements with post-Communist Polish and Ukrainian state archives to allow American Jews on-site access to genealogical data.
A former private detective, Weiner began researching her own family history more than two decades ago. She got so involved that she became the first certified Jewish genealogist -- and turned her personal interest into a business.
Her home base in New Jersey is crammed with books, publications, maps, foreign phone directories, old photographs and postcards and other material about Eastern Europe. She lectures and writes a syndicated column, and has written and published comprehensive books on Jewish genealogical resources in Poland, Ukraine and Moldova.
Weiner regularly travels to Ukraine, Belarus, Poland and Moldova to carry out research for clients and also takes individuals or groups on research trips. In 1990, she organized the first Jewish genealogy tour to Poland that was officially sanctioned by the Polish State Archives and other state authorities.
For those who can't make the trip, Weiner brings back copies of documents as well as photographs, souvenirs and videotapes of the ancestral town.
Sometimes, too, she puts American clients in touch with long-lost kin. This happens very rarely in Poland, where few Jews remain, but, she says, it is not uncommon in countries of the former Soviet Union.
Today's Jewish genealogy phenomenon is part of a general boom. Last spring Time magazine ran a cover story on the genealogy craze, noting that millions of people of all ethnic backgrounds are looking for their roots.
This is related to a burgeoning sense of ethnic identity and awareness in recent years. "Roots" -- the book by Alex Haley and the resulting TV mini-series in the late 1970s -- played a major role, for example, in showing that genealogy was not the exclusive property of WASPs.
When "Finding Our Fathers" by Dan Rottenberg, the first how-to book on Jewish genealogy, was published in 1977, it represented the first time that many Jews learned it was possible to trace their family heritage -- despite the ravages of the Holocaust, and the anonymity of earlier mass immigration.
"There is no question that the Holocaust is a major reason why so many of us want to trace our roots," said Sallyann Amdur Sack, editor of Avotaynu, the International Review of Jewish Geneology, now in its 15th year of publication. "We have noted a sense of belonging to a long chain of history, one which Hitler came close to severing. In part, genealogical research represents a driven need to deny Hitler a victory.
"As the 'help desk' for the project, I have received countless inquiries of all varieties," wrote Sack in Avotaynu. A woman in Canada "wanted to know why none of what she called 'the major Jewish organizations' have done this. Maybe the answer is that organized Jewish genealogy now is MAJOR.''
For more information, see the Web sites www.JewishGen.org, www.avotaynu.com. Miriam Weiner's Web site is www.rtrfoundation.org