Iñaki Buenaposada took the books when he was a 16-year-old language student in the UK city of Cambridge, local daily The Cambridge News reported on Monday.
"One day I saw a black bag in the garage (of the house where I was staying) and I thought it was rubbish. I saw the books and took three of them."
But when the lady of the house became upset that night, the young Buenaposada was too ashamed to say anything. "I think it was because I wasn't man enough to face up to her at the time and tell her I was guilty."
He has kept the books — including an old copy of Dickens Oliver Twist — ever since, but the feelings of guilt haven't left him.
This week, however, a 40-year-old Buenaposada returned to the scene of the crime — although he can't remember the name of the street where he lived, or even the name of the couple he stayed with.
"I want to return the books to the people I took them from, that is my only reason for coming," he told The Cambridge News.
Buenaposada didn't have any luck finding the owners of the books but has vowed to keep up the search.