"Jakob der Lügner" is a novel by Jurek Becker, published in 1969. It tells the story of Jakob, a Jewish man living in the Warsaw Ghetto during World War II. To protect his fellow inmates from despair, he fabricates stories about the outside world, claiming that the Allies are winning the war. His lies provide hope but also lead to unforeseen consequences. The novel explores themes of truth, deception, and the human spirit in the face of adversity. It has been adapted into a film in 1975, further popularizing its poignant message about survival and the power of hope amidst tragedy.