CHICAGO (CBS) — When the Chicago Public Library announced its first amnesty in 20 years, it didn’t expect to get back a rare classic.

After 78 years away, a limited edition copy of “The Picture of Dorian Gray” by Oscar Wilde has returned to the Chicago Public Library.

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Commissioner Brian Bannon says the daughter of a late patron found the book in an attic years ago. After worrying about fines and punishment, she took advantage of the amnesty, he says.

“We know that sometimes people feel bad about late fines, and it keeps them from using the library,” Bannon says. “This is as much about getting patrons back as it is about getting materials back.”

As for other long-overdue treasures still owed the library, Bannon says there could still be some out there.

“The record-keeping in that area was not as good as it is today,” he says.

The amnesty runs through Sept. 7.