Some people collect stamps; others, salt shakers. Barbie dolls are popular. Sports cars are clearly cool. Apricot pits used to be big in Jerusalem grade schools.

Stephen Durchslag goes for haggadot. And with 4,500 − give or take a few exodus-from-Egypt re-tellings − the 71-year-old Chicago intellectual property lawyer owns the largest-known private collection of haggadot in the world.

It started 30 years ago when Durchslag and his wife Ruth wandered into a Jewish bookstore on Manhattan’s Upper East Side and, poking around, stumbled upon an 1867 haggadah from Livorno, written in Hebrew and Ladino.

They liked it. They bought it. The rest is history.

“That first haggadah, the one that started my collection, said something to me; it both took me back to my own family,” explains Durchslag, “and on another level it took me even further back. Here were voices from the past saying, “‘Save us, remember us, we who may have had little freedom.’” Durchslag’s collection, a small sample of which will be exhibited at the University of Chicago starting this week, includes everything from New Age haggadot − which speak of the exodus as a metaphor for escaping the narrow confines of the self − to valuable limited editions worth tens of thousands of dollars.

In all, Durchslag owns haggadot in 31 languages, from Medieval Italian to Afrikaans to Judeo-Tat, a language related to Persian that is spoken in the Caucuses. There are new haggadot and old ones dating as far back as 1485. There are satirical accounts, and over 700 kibbutz versions, some of which celebrate Israel but omit the name of God. There are beautiful, rare bound books, and there are flimsy booklets once distributed by Jewish communities’ local kosher butchers.

In Israel this week, Durchslag took some time − over a fresh lemonade at the Tel Aviv port, and between phoning in bids on three kibbutz haggadot being sold at a Judaica auction in Petah Tikva − to chat about his unusual Passover passion.

“Growing up in Chicago, my parents would always have seder at home,” Durchslag recalls. “Everyone would come over. The women would have been cooking for days. My job was to lug the Passover dishes up from the basement to our second-floor apartment. The younger cousins would get tipsy from the wine. And the men would sit at one side of the table reading the haggadah to themselves, basically. It was a time of enormous family warmth.”

“Learning where each haggadah comes from has become my way of learning history and culture of my people,” adds Durchslag, who has recently gone back to school to get a master’s degree in Jewish studies at the Chicago Divinity School, working on − what else? − haggadot. “It’s like they represent a breathing part of Judaism.”

Although the structural arrangement of haggadot is generally the same, relaying the story of the Jews leaving Egypt, complete with blessings, rituals, songs and Talmudic commentaries, the text is something of an open narrative that can be expounded on − something different generations have long been doing, pursuing both tradition and experimentation.

Visually, as the haggadah was meant for home use, it was never subjected to the restrictions against graven images. As such, the text is presented as an illustrated book, which can also reflect a wide variety of aesthetic approaches, representational needs, and cultural and political agendas.

Durchslag spends “a great deal of time” cataloging, translating and speaking about the collection, always keeping a list of what he owns on hand and making sure not to buy any duplicates, he says. The entire collection is kept at home in a specially built library his wife teasingly calls the family’s “Library of Congress.”

While the rest of the Durchslags may sometimes tease him for such obsessive haggadah collecting, many of them have been bit by the haggadah bug themselves. Ruth Durchslag, a psychologist turned reform rabbi, volunteers in a Chicago prison, teaching spiritual yoga to female inmates, and also reading haggadah with them, emphasizing the theme of freedom.

Eldest daughter Rachel, a social worker who set up a charity alliance in Chicago against sexual exploitation, has put together her own version, an “Anti-Trafficking” haggadah that focuses on freedom from exploitation as a Jewish value.

The youngest Durchslag daughter, an artist in New York, is “not haggadah-oriented,” her father admits. “Not yet,” he corrects himself. There is always this year’s seder to win her over, as the story of slavery, plagues and freedom is once again passed down along the generations.