A 1787 first-edition book signed by Thomas Jefferson.

A rare copy of “The Journal of Major George Washington.”

A version of Isaac Newton’s “Principia,” among the most influential books in science, said to be worth $900,000.

The archivist who oversaw a special collection of rare books at the central library in Pittsburgh walked out of the building with these and other items — sometimes in plain sight — and sold them to a local bookstore owner, authorities said, in a scheme that lasted nearly 20 years.

The library archivist, Gregory Priore, 61, and the bookstore owner, John Schulman, 54, were arrested on Friday on numerous criminal charges including theft and criminal conspiracy, authorities said.

They are accused of trafficking several hundred rare books, maps and other items worth more than $8 million in total, records show. More than $1 million worth of items, including the Newton volume, have been recovered.

Even in the niche world of rare-book dealers, the value of the items stolen is stunning, said Michael Vinson, a dealer based in New Mexico who is a member of the Antiquarian Booksellers’ Association of America.

“This is a huge deal,” Vinson said, noting that most rare-book dealers have annual sales between $500,000 and $1 million.

Priore, the archivist, could not be reached for comment on Friday night. A lawyer representing him did not immediately respond to an email.

Schulman did not respond to requests for comment. His lawyer, Robert G. Del Greco Jr., told The Pittsburgh Post-Gazette that his client was a “titan” in the book community. “The complaint sets forth serious allegations, and we are treating them as such,” he said.

The partnership between Priore and Schulman began in the late 1990s, according to an affidavit filed by the Allegheny County District Attorney’s Office, which investigated the case.

Priore told authorities that he approached Schulman about selling some items in the library, but that Schulman later “goaded” him on.

Priore was the sole archivist for the collection of rare books, maps and other items at the Carnegie Library of Pittsburgh, the city’s public library system. He oversaw about 30,000 items in the collection and controlled who had access to it, the affidavit said.

Schulman and his wife own Caliban Book Shop, a block or so from the library, records show. He dealt in rare books, and was listed as a member of the Antiquarian Booksellers’ Association of America.

Over the years, Priore told authorities, he removed items from the library — sometimes he used an X-Acto knife to remove a part of a book, and other times he simply carried out a whole book or map — and dropped them off at Caliban Book Shop on his way home from work.

Schulman paid the archivist up front, records show, and then sold many of the items, including some to major book dealers.

From 2010 to 2017, Priore received about $117,000 in checks from Caliban Book Shop, according to the affidavit. Priore also deposited $17,000 in cash into his account in that time period.

Vinson, who was acquainted with Schulman professionally, said it is possible that other dealers did not ask Schulman where he got the books because dealers rarely share the source of their merchandise.

“They know him, they trust him, they don’t have to ask him any questions about it, because he’s trading on that trust he’s built up over so many years,” Vinson said.

It is unclear how much money Schulman made from the deals.

Priore told authorities that he used the money to stay “afloat” and help pay tuition for his four children. “I should have never done this,” he said. “I loved that room, my whole working life, and greed came over me.”

“I did it,” he said, “but Schulman spurred me on.”

Priore said he stopped selling in late 2016 because he learned that the library was going to do an appraisal of the collection the next year.

Appraisers discovered missing items and books that had been “cannibalized,” with entire portions removed, according to the affidavit.

Priore was fired in 2017, records show. Suzanne Thinnes, a spokeswoman for the Carnegie Library of Pittsburgh, said in a statement that the library was grateful the investigation had ended with arrests.

She added, however, “We are deeply disappointed that at the center of this case are two people who had close, long standing relationships with the Library.”

Vinson said the news of the charges was the talk of the rare-book community on Friday. “The phones are burning up,” he said.

“These were great rarities and treasures,” he said. “I’m just shocked at the depth of this thing.”

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