Authorities threw the book at 12 people Tuesday, accusing them of checking out pricey textbooks from a public library system outside Washington to sell for quick cash.
The Prince George's County Memorial Library System in Maryland lost $87,000 worth of material from thefts between November 2008 and July 2009, county prosecutors said.
Textbooks and other works were quickly sold to used book stores at a fraction of their original value, investigators said.
Prince George's County authorities said the suspects, at least some of whom were related, withdrew close to the limit of 75 books from 12 of the library system's 18 locations. Each is charged with theft over $500 and faces a maximum penalty of 15 years in prison.
Authorities said all 12 charged Tuesday are Maryland residents. They range in age from 20 to 51.
Some college libraries also were hit by some of the same suspects, officials said.
"They're traveling quite far and wide for the little bit of money they get," said Mary Eilerman, chief of security at Harford Community College, also victimized. "They were ripping off the bar codes and handing them over to book consignment shops as quickly as they could."
Eilerman said a $100 textbook would yield about $3 or $4 at a consignment shop. She said one of the suspects told her she was using the cash from the thefts to buy Ecstasy.
Bridget Warren, a spokeswoman for the Prince George's library system, said the 75-book limit is reviewed annually, along with all policies. The loss represents about 2 percent of the $4 million that the system spends on materials annually.
Dealing with thefts is tough for libraries, said Jim Rettig, immediate past president of the American Library Association.
"We want these things to be used. We want them to go out," said Rettig, university librarian at the University of Richmond in Virginia. "If we wanted to prevent theft, we wouldn't let them leave the building."