Don Quixote of La Mancha, also known as 'The Knight of the Rueful Countenance,' is a classic novel by Miguel de Cervantes Saavedra. The story follows an aging nobleman who becomes obsessed with chivalric tales and decides to embark on a quest to revive knighthood. He dons an old suit of armor, takes up the name Don Quixote, and sets off on adventures, often mistaking ordinary people and objects for fantastical creatures and challenges.

Throughout his journey, Don Quixote encounters various characters, including his loyal squire, Sancho Panza, who provides a contrast to his master's idealistic view of the world. The novel explores themes of reality versus illusion, the nature of heroism, and the importance of dreams. Cervantes masterfully blends humor and tragedy, making Don Quixote a profound exploration of human nature and the pursuit of lofty ideals.