A free mini-library has opened in a New York underground subway station -- the first of its kind in Manhattan.

The Little Free Library book exchange was unveiled this week at the 145th Street and St. Nicholas Ave subway station, outside the NYPD’s Transit District 3 Precinct.

The little library only stands about five-feet tall. Open the door and anyone is free to take a book. All the organizers ask it that readers leave a book behind, to fill the gap. The non-profit organization started the initiative in the hopes it would get more people reading.

“We’re trying to get books to our children”, NYPD Officer Damieon Frey explained.

Little Free Library has outlets all over the world. There are over 10 in the city already, but this is the first in an underground station. NYPD Transit plans to place a Little Free Library in each transit precinct eventually.

Little Free Library founder Todd H. Bol said there will be books for all age ranges and many that will appeal to young children.

“We did this partnership with Marvel, and Marvel is going to give an ongoing supply of books… Disney will send two years supply of Marvel books and comics.”

For those concerned about people mistreating the library and the books inside, Frey points out that the box sits directly outside the precinct, allowing for constant supervision from NYPD officers.

He added that readers aged 13-18 would act as mentors to the younger children, reading with them after school at the Little Free Library outside the precinct, as part of the NYPD Explorers Program.

To learn more visit their website.