Dan Rottenberg got his Russian grandmother's bright red hair, her crystal blue eyes, and, at her funeral in 1958 when he was 16, a life-long desire to know who he was.

His quest went beyond the child's questions of "Who am I?" and "Where did I come from?" - queries that usually get quick answers like "From Mommy and Daddy" - to the larger question of where the whole family came from. At his grandmother funeral, the teen-age Rottenberg found himself copying the names and dates from relatives" tombstones and entered the ranks of genealogists.

"Genealogy is simply history on a personal scale," Rottenberg is fond of saying. But history has had a tendency to step high, so that in the past it's only been the highsteppers - the kings, queens, nobles, generals and philosophers - who've had a personal history. And in America, until Alex Haley's book "Roots," it's mostly been the primary preserve of Anglo-Saxon Protestants.

For Rottenberg's grandmother, like thousands of Jews, history had nothing to say except Jewish immigrants came to American in the 1880s after the Russian pogroms and the anti-Semitic May laws Yet unlike other immigrants, Rottenberg says, Jews have special advantages in tracing their ancestors.

Rottenberg, who has traced his and his wife's family back to the early 1800s and found one line that goes back to the Khazar kingdom in the Crimea, which dates to the 8th century, notes that there is only a finite number of Jews in the world.

In his book, "Finding Our Fathers, Our Links With the Past," which recently brought him to Washington on a promotion tour, Rottenberg states: "There were never more than 17 million (Jews) at any one time, and there are only 14 million today - and by and large Jews have tended to intermarry within Judaism. Thus most Jews are related to one another somewhere in the past, however distant."

Even though it is unlikely that a medieval Jewish family kept family records, Rottenberg says the rabbis as a class considered keeping such records a solemn duty.

"The rabbis in Eastern Europe wrote "responsa" and commentaries on the Talmud (the body of biblical and rabbinical interpretations)," says Rottenberg. "They always included genealogical information on the author. There were about 1,500 rabbis who wrote these commentaries, so the mathematical probabilities of having one in a Jewish family are good."

Rottenberg, whose book is a kind of how-to on tracing Jewish genealogy, says his search has been greatly aided by Haley's book and the subsequent television series. "When I first started doing this," he recalls, "people I'd call were very suspicious. They thought I was some kind of con man. Lately I don't run into that suspicion, thanks to Haley."

In 1969, Rottenberg sent out his compilation of family history to 200 relatives, most of whom he had never met. After receiving copies of the book, two families living next door to one another on Long Island discovered they were distantly related. Their children, who had been playmates for years, ran through the streets shouting, "We're cousins, We're cousins."

Not everyone was as enthusiastic about Rottenberg's family genealogy, though many responded with new information.

Rottenberg, a free-lance writer who lives a Philadelphia, is philosophical about those relatives who were uninterested, saying merely, "What the grandson wishes to remember, the son wishes to forget."

Rotteberg, however, doesn't want to forget any of his relatives, especially, his paternal great grandfather.

"I'd like to do a genealogy based on family traits sometimes, because I feel a special afinity to my great grandfather Lousi Margulies," he says. "He was an adventurer, a man born in Austria who went to England when he was 14 and eventually worked on a ship that went to China. He finally settled in New York. He owned some tenement buildings in Brooklyn, but he was a very kind man. He not only would not make his tenants pay the rent - they were very poor - but he usually gave them money."

Rottenberg also says that genealogy and getting to know one's ancestors puts "one's own problems in a better persepctive. There is something to be said for struggle and persecution."

His red-haired, blue-eyed grandmother was the daughter of a woman who was married at 18 to a man she barely knew, was a mother at 19, and said good-bye forever to her family in Suwalk, Russia, when she was 20 to join her husband in America. There life was rough and poor, but they survived, Rottenburg notes.

"Her husband's sister married a man of some wealth and stayed in Russia, only to be wiped out in the pogroms," he says. "The fact that he came to America meant his descendents - and I'm one - are still here to admire their courage."