What We Can Know is the 18th novel by author Ian McEwan published in 2025 by Jonathan Cape, set almost a century in the future in a UK partially submerged by rising seas. The book is centered on Tom Metcalfe, an academic at the fictional University of the South Downs investigating a lost poem, read aloud in 2014. 
McEwan has described the book as a work of science fiction “without the science."