Disappearing books: Evolution of subway reading
27 February 2015 Last updated at 00:10 GMT
Dutch photographer Reinier Gerritsen has been photographing in the New York subway since 2008. Around 2011, he began to notice that something was changing. As each year passed, more and more people were abandoning printed books in favour of smartphones and tablets.
He began to document the phenomenon by photographing people reading books on the New York subway. His latest work - aptly titled The Last Book - brings together hundreds of portraits, each one named after the book the person is reading.
He spoke to Colm O'Molloy about his work.
Images © Reinier Gerritsen, courtesy Julie Saul Gallery, New York