Underland: A Deep Time Journey is a book by Robert Macfarlane and the sequel to . Initially published in English on 2 May 2019 by Hamish Hamilton in the UK and on 4 June 2019 by W. W. Norton & Company in the US, the book has been translated into over a dozen languages. An audiobook, read by Matthew Waterson, was also released in June 2019 by HighBridge Audio.