Tunnel Under the World is a science fiction novel by Frederik Pohl that explores the nature of reality, identity, and the human condition. The protagonist, Guy Burckhardt, wakes up from a terrifying nightmare of explosions, fire, and gas. As he tries to piece together what happened, he begins to question the nature of his own reality. Is the world around him real, or is it just a simulation? And who is he, really? Tunnel Under the World is a thought-provoking and unsettling novel that will stay with you long after you finish it.