"The Luzhin Defense" is a novel by Vladimir Nabokov about the brilliant, yet mentally unstable, chess player Alexander Ivanovich Luzhin. The book recounts his rise in the world of chess, his obsession with the game, and his gradual descent into madness as the line between reality and chess combinations blurs. The novel explores themes of genius, isolation, and the tragic fate of a person unable to adapt to ordinary life.