Josh Reynolds for the Boston Globe

Librarians Jessi Snow (left) and Laura Koenig work with young adult readers at the Copley Library.

John Tlumacki/Globe staff

Laura Koenig (left) and Jessi Snow talked books with teens in the custody of the Department of Youth Services.

Josh Reynolds for the Boston Globe

Maya Escobar is one of a mushrooming corps of librarians in Greater Boston working to put books in the hands of young readers.

Josh Reynolds for the Boston Globe

Cambridge librarian Maya Escobar spoke with visitors at an event in the Teen Room.