By Scott Heller

South Hadley, Mass.

Aaron Lansky had a plan. Not a modest plan, for sure, but a plan with a beginning and an end.

"I planned to rescue all the Yiddish books left in the world and then go back to graduate school," he says.

That was 1980, and Mr. Lansky, then 24, was a graduate student in Jewish studies at McGill University. As he delved into Eastern European literature, he realized how few Yiddish- language books were available. Time mattered, too, because a generation of Yiddish speakers who saved old books was dying out, its treasures often ending up on the trash heap.

Experts told him there were probably no more than 70,000 Yiddish books to be saved. By placing advertisements and through word of mouth, he began collecting what was out there, traveling by van to empty out basements and garages.

These emergency rescue missions led to the establishment of the National Yiddish Book Center, now a world-renowned clearinghouse for the collection and sale of Yiddish materials. Mr. Lansky won a MacArthur grant for his efforts in 1990.

Today the center has amassed some 1.3 million volumes in Yiddish and in translation, with 30,000 separate titles. "No one in the entire world comes anywhere close" to matching that number of Yiddish-language books, says Jeffrey A. Aronofsky, the center's director of book collection and distribution.

Yiddish, a polyglot mixture of German, Polish, and Hebrew, was spoken by three-quarters of the world's Jews for nearly 1,000 years. The Holocaust wiped out one of every two Yiddish- speaking Jews. Assimilation in America has led to further erosion, as has the promotion of Hebrew as the official language of Israel.

If Yiddish is spoken at all in today's American Jewish households, it is the language parents use when they don't want their children to understand what they're talking about. Yet Mr. Lansky sees Yiddish not as the stuff of nostalgia, but as a vital piece of Jewish cultural history.

"Book collection is not his goal," says Leonard B. Glick, a long-time friend and a professor of anthropology at Hampshire College. "It is only a means to an end. Aaron's goal is nothing less than the rejuvenation of American Jewish life."

Mr. Lansky helps himself to barbecued chicken and keeps an eye on his children one summer afternoon on the campus of Mount Holyoke College, where the center holds an annual summer program in Yiddish language and culture.

The week-long program includes lectures on Yiddish literature by Mr. Lansky, and on the history of European Jewry by Mr. Glick. Attendees also get to work on their language skills and take workshops in Yiddish music and theater.

Many here can understand and speak Yiddish, but few can read or write it. At meals, several tables are set aside for Yiddish speakers. Almost no one sits there at first -- the signs announcing the tables are written in Yiddish.

Since books are the center's mission, a trip to its massive warehouse is a highlight of the summer program.

The peppy Mr. Aronofsky gets a laugh from the group -- still tired after the climb up the stairs -- when he explains the layout and the pricing system. "We have a special today," he says, "if you're not ferblunget yet." He adds: "There are signs explaining the prices. And we ship anywhere in the world -- we're the L.L. Bean of Yiddish books."

The center rents two floors, each twice the size of a football field, to house its books. One floor of the warehouse is filled with books that have yet to be sorted; the other is divided into sections for works in Yiddish and for translations.

Phyllis Ross asks Mr. Aronofsky for help locating a yizkor book from the town of Bialystok, near the border of Russia and Poland. She is trying to translate her late father's account of his years in Europe, to pass it along to her children and grandchildren, who don't know Yiddish at all.

She hopes that the yizkor book -- one of a number that Jews put together after World War II to document their destroyed communities -- will offer more information about his life before he emigrated to the United States. But the books are very valuable and rarely turn up for sale.

Like Ms. Ross, Carol Slater is here to make sense of a document with personal meaning. When her mother died, Ms. Slater found notebooks kept by her grandmother. They included details for the stories that Ms. Slater's grandmother sometimes wrote for the Jewish Daily Forward, the Yiddish- language newspaper. "There were a couple of Bubbe Sonia's little pamphlets there, written in Yiddish script," says Ms. Slater, a professor of psychology at Alma College. "Maybe I can learn enough to figure out what I have." In the meantime, she is looking for a piece of Yiddish calligraphy suitable for framing.

After a while, the Yiddish-language half of the warehouse is virtually empty of shoppers. Instead, they are buying works in translation, kids' books for their grandchildren, T-shirts, and mugs.

The center's signal achievement has been to place Yiddish collections in libraries in the United States and throughout the world. Some 525 libraries in 20 countries have purchased books.

The center has prepared two sets of key Yiddish texts. The basic collection comprises 500 volumes. The more comprehensive collection, which Mr. Aronofsky says is designed for graduate- level research, has 1,000 volumes.

Libraries that want customized collections work with Mr. Aronofsky to identify titles. Besides its frequently updated catalogue, the center also puts together subject lists on such topics as women's literature and radical movements.

To locate materials, the center depends on a network of zamlers -- "collectors" -- around the world. Their discoveries sometimes come out of the blue. A Jewish community center in Providence, R.I., says: Pick up 25 boxes of books by tomorrow or out they go. A decrepit Brooklyn garage turns out to house 70,000 pieces of Yiddish sheet music, most of it in mint condition.

Thanks to the center, libraries in Sweden, Belarus, Estonia, and Australia now have substantial Yiddish holdings. Two Chinese research institutes recently received collections provided by Jonathan Goldstein, a professor of East Asian history at West Georgia College. Mr. Goldstein, a scholar of Jewish communities in China, bought works both in Yiddish and in translation to supplement the Judaic-studies holdings at institutes in Shanghai and Nanjing.

Typically, a library that wants to bolster its Yiddish holdings will work with the center to identify a donor to underwrite the cost of the purchase. The center also depends on institutional and individual memberships.

Among its largest clients are Yale University and the University of California at Los Angeles. The center has a unique relationship with the YIVO Institute for Jewish Research, which receives books on permanent loan. In return, YIVO sends books it doesn't need to the center for distribution elsewhere. Zachary M. Baker, YIVO's head librarian, says the center has helped fill gaps in YIVO's collection, including Latin American materials from the 1920s to the 1950s.

Though he is not a professor himself -- he never did make it back to graduate school -- Mr. Lansky draws heavily on his academic mentors from Hampshire College. The center is in western Massachusetts because he got his undergraduate degree at Hampshire. Mr. Glick, his professor, oversaw several of Mr. Lansky's independent-study projects in Jewish history.

The connection will grow even stronger when ground is broken for the center's permanent home, in an apple orchard on the Hampshire campus. According to architectural plans, the book holdings will be at the heart of a living museum of Yiddish cultural history, also to include a studio for recording oral histories and a computer that "speaks" Yiddish dialects.

So far, Mr. Lansky and his board of directors have raised more than half of the necessary $6.2-million for the center's new home. Although it is a grassroots operation that depends on membership fees and small donations, the center is eyeing bigger donors.

In July, National Public Radio began distributing a 13-part series of audio recordings of Yiddish, Hebrew, and Russian short stories. The center co-produced the series with a California NPR station, recruiting Leonard Nimoy, Elliott Gould, and Lauren Bacall, among others, to read.

For Mr. Lansky, the joy of Yiddish is that it is the mark of a culture that straddles the old and the modern worlds. In one of his lectures during the summer program, he contrasts the writings of Isaac Bashevis Singer, the Nobel Prizewinner, and I.L. Peretz, a far less well-known writer in Yiddish, who died in 1915.

Singer, he explains, was ultimately a pessimist, who didn't believe that religious tradition and modern life could be reconciled. Peretz, on the other hand, laid out a way to engage the modern world while staying true to Jewish cultural values. "Yiddish won't survive as a spoken language except among the Hasidic people," Mr. Lansky predicts. But this does not minimize its importance.

"History is our lifespring, our identity," he says. "Jews have to come to terms with that."

"Yiddish," he adds, "has not said its last."