So he and friends started visiting the city's old Jewish neighborhoods, ferreting out the novels of Mendele Sforim and I.L. Peretz while sipping tea with elderly Jews and listening to their emotional stories about the significance of each volume. For them – mostly immigrants from Eastern Europe – the books were the inheritance they were leaving to the world.

"We sensed immediately that we were witnessing an epochal change in Jewish history," recalls Mr. Lansky, now president of the National Yiddish Book Center. "Books were being destroyed at an alarming rate and with them an entire culture."

So he took a leave of absence from McGill and began driving up and down the East Coast hunting for Yiddish books. Experts dismissed him as a meshugener, a crazy person. They estimated that only 70,000 Yiddish books remained in all of North America, and 99 percent of Jews couldn't read them anyway.

That was 1980. Today, more than 1.5 million Yiddish books have been recovered, and Aaron Lansky and his army of zamlers, or volunteer book collectors, have found most of them – in attics, basements, sheds and garages. He once pulled 8,000 volumes from a Dumpster in Manhattan; he found a priceless collection of Yiddish sheet music in a warehouse under the Brooklyn Bridge.
He has several explanations for why the experts were so wildly off.

"Jews turned out to be infinitely more avid readers than anyone had realized," he says. "But there was also a pessimism in the old Yiddish world, particularly among Jews who had seen their entire culture ripped out by the roots in the Holocaust. Why bother about the past. It was all over."

At first, Mr. Lansky stored his treasures in his parents' attic in New Bedford, until the house began to list. He then rented an empty school in Amherst and after that an old skating rink in Greenfield and abandoned factories in Northampton and Holyoke. The books kept coming, as many as 5,000 a week in the early years; at one point Mr. Lansky had to ask his congressman to intervene with the local post office.

In 1997, after nearly two decades of collecting and lecturing and schmoozing with prospective donors, he moved into the $8 million center at Hampshire College. He chose Amherst, he says, because it was a "Jewishly neutral location," meaning outside the traditional urban centers and divisive debates that go with them.

The center is a collection of small wood buildings with hipped roofs and weathered siding, set in an apple orchard against a backdrop of low undulating hills. The basic forms are those of a shtetl or village in Eastern Europe, inflected with the simplicity and frugality of rural New England.

"We wanted the buildings to be evocative without doing some sentimental, storybook treatment," explains architect Allen Moore. "We used familiar materials and exposed the structure and tried to create a feeling of intimacy."

Visitors cross a short bridge to a bright lobby; library, bookstore, classrooms and offices veer off in one direction, exhibition galleries in another, including one displaying the last Yiddish linotype machine in America. And straight ahead is a tall open space containing worktables and stacks supporting 125,000 books. For anyone who thought Yiddish literature was dead, it is an astonishing sight and a symbol of the center's mission to supply Yiddish books to university and research libraries around the world. So far, it has provided core collections to 450 institutions in 25 countries.

The bibliographical deluge of the early years is now a trickle of 500 to 1,000 books a month, which has allowed Mr. Lansky and his staff to turn their attention from collecting and cataloging books to developing a new audience for them. The center recently digitized its permanent collection with the help of a $500,000 grant from Steven Spielberg. Readers can now order any title online for approximately $25. The center also sponsors lectures, film series and symposia. It has also just launched a translation program to make the best Yiddish literature available in English.

The Jews in Montreal and Brooklyn and Baltimore who gave their books to Mr. Lansky and his zamlers acted on faith that a younger generation still cared enough about Yiddish culture to preserve it. With the success of the National Yiddish Book Center, that faith has been rewarded.