US novelist Paul Auster's new book, 4321, is a "what if" story about the unfolding of an American life in the mid-to-late 20th Century.

Although Auster started work on his 900-page epic when the idea of a President Donald Trump was on nobody's radar, some critics are calling it prophetic.

Paul Auster spoke to BBC Newsnight's culture correspondent Stephen Smith about the book, Trump and the tragedy that changed his life forever.