Now, more than ever, researchers are using the books in Thomas Jefferson’s library. The following is a guest post by Mark Hartsell, editor of the Library of Congress staff newsletter, The Gazette.

Mark Dimunation stands in a vault near the rare-book reading room and eyes a dozen volumes on a half-filled shelf, each bearing a small green ribbon.

“It’s been a little slow,” says Dimunation, chief of the Rare Book and Special Collections Division, as he scans the titles.

The books all were drawn from the “Thomas Jefferson’s Library” exhibition at the Library of Congress, and each ribbon indicates a book once owned by Jefferson himself.

The exhibition is one of the Library’s most popular attractions – a physical representation of the intellectual curiosity of a Founding Father and a tangible connection to the towering historical figure who personally picked out and read every title.

Jefferson’s books aren’t, however, just for show: More than ever, Dimunation says, those volumes serve as a working collection that helps scholars gain a better understanding of Jefferson and his world.

Once infrequently used, Jefferson’s books now are regularly requested by researchers – typically 15 to 18 volumes each week.

“Not only is Jefferson’s library the foundation of the Library of Congress, it’s the foundation of the accessible library,” Dimunation says. “These books aren’t being artfully arranged to look used. We’re actually pulling books out on almost a daily basis. The reason these books look like they’re coming and going is because they’re coming and going.”

Over the first four days of this “slow” week, researchers requested the nine titles resting on that vault shelf – among them, Jefferson’s copy of the Constitution; John Adams’ “A Defence of the Constitution”; a work about Italian musical theater; two histories of the American Revolution; and “Virginia,” a book published in 1650 by Edward Williams extolling the virtues – the potential for silkworm farming, for instance – of what would be Jefferson’s home state.

The increase in research requests in recent years is due in part, Dimunation says, to the exhibition, which re-creates the library purchased by Congress from Jefferson after the British burned the U.S. Capitol in 1814 and, with it, the congressional library.

Jefferson sold 6,487 of his own books to Congress as a replacement – volumes that became the foundation of the Library of Congress collections.

Another fire, in 1851, destroyed two-thirds of those books. In 1998, the Library of Congress decided to reconstruct Jefferson’s library by seeking out identical editions of titles lost in that blaze.

The exhibition opened in 2000, displaying the original Jefferson books that survived the fire – marked with the green ribbons – alongside those identical editions acquired from elsewhere in the Library collections or by purchase or donation.

The exhibition and its online counterpart, Dimunation says, have raised awareness among researchers of available titles. “People are beginning to find them online,” he says.

There is no typical research topic – the subject matter is as wide-ranging as Jefferson’s intellectual interests, from Restoration Theater to Persian history to Palladian architecture to the spread of Italian philosophical ideas during the 18th century.

No subject was too obscure to draw Jefferson’s interest – a boon to scholars two centuries later. One researcher recently requested a book on phlogistons, a hypothetical substance once thought to be the combustible part of all flammable materials.

Jefferson had it covered.

“The topics can run pretty wild,” Dimunation says.

About one-third of requests are related to research about the man himself – Jefferson and slavery, for example, or Jefferson and music (he played the violin and made annotations on music).

But most researchers are studying topics related to the period, not the person, and they often don’t know they are requesting books that once belonged to Jefferson – a sometimes-intimidating surprise.

One researcher requested a book on Restoration Theater and was shown how to handle the volume and asked to keep the green ribbon visible in its pages.

“Why?” she asked.

Told the ribbon indicates the book belonged to Jefferson, she threw her hands back and said, “I don’t want to work with it.”

“You’re going to have to,” Dimunation told her. “It’s the only copy in the library.”

The most-requested volumes, Dimunation says, are Jefferson’s original copies of “The Federalist,” the Koran and “Notes on the State of Virginia,” a book he authored.

Scholars often want to study this Koran – a 1764 edition of a translation produced by George Sale three decades earlier – to better appreciate Jefferson’s own understanding of Islam. Sale’s Koran was the first to be translated directly from the Arabic into English and is credited with introducing the sacred text to the West.

“The researchers want to see what the English version of the Koran is imparting to Jefferson in terms of his understanding of Arabic law,” Dimunation says.

For many, it’s also a moving experience.

“I think for people of Muslim faith, it’s profound,” Dimunation says. “It seems to be a profound moment.”

In his day, Jefferson owned the largest personal library in the United States. He had titles that couldn’t be found anywhere else in the country, Dimunation says, and people traveled long distances just to see the library and use the books.

Two centuries later, they still do.