Library user Gil said his book was turned in late because, "My excuse runs like a library-Greek tragedy where members of the same family try to do each other in with overdue fines and records."
The San Francisco Public Library received back nearly 30,000 overdue books during a two-week amnesty period last month, the library announced Thursday.
The library estimated the total value of the 29,228 returned books at $730,000.
One of the oldest books returned was a 1947 copy of George Bernard Shaw's "Man and Superman." It had a due date of Jan. 29, 1964 and was borrowed from the Presidio Branch Library.
The returnees saved themselves a total of $55,165 in overdue fees, the library reported. Along with the returned books, they were also asked to submit "excuses" for their lateness.
One apologetic library patron, known only as "Antonio," blamed his tardiness on a two-month abduction by aliens, the library said.
Another library user, known as Fredrick, said he enjoyed the book he held onto for so long that he thought it was his own copy and library client Lauren said she was too busy reading the books to return the books.
Captain Chesly B. "Sully" Sullenberger III, known now as the Hero of the Hudson because he safely landed a jetliner on New York's Hudson River in January, spoke up for the amnesty campaign and admitted he was an overdue offender.
Sully urged library users to return books no matter what what the reason for the lateness, "Maybe you're just looking for a really, really good excuse, like it got lost in the Hudson River."
Bay City News contributed to this report.