A rare first edition of Charles Darwin’s “On the Origin of Species” has been returned to a Halifax university library, six years after it was stolen.

The RCMP turned over the book -- considered to be the most important work on evolutionary biology -- to Mount Saint Vincent University on Thursday.

The book was stolen from the university’s library in 2009. In 2013, John Mark Tillmann of Fall River, N.S., pleaded guilty to possession of stolen property, along with numerous other charges.

The stolen property included the valuable copy of Darwin’s book, as well as thousands of other books and artifacts.

Tillman was sentenced to nine years in prison.

The RCMP say the stolen Darwin book was sold in 2012 to someone in the U.S.

Earlier this month, Const. Darryl Morgan went to New York to retrieve it from the U.S. Department of Homeland Security.

“Homeland Security escorted me through security … and sat with me at the airport in New York until my flight departed,” he said.

The university says it will keep the book inside an alarm-activated cabinet. Anyone wishing to look at it will have to make an appointment.