E. T. A. Hoffmann's 'Der Sandmann' is a seminal work in German Romantic literature, exploring themes of madness, obsession, and the blurred lines between reality and fantasy. The story follows Nathanael, a young student who becomes fixated on the mysterious figure of Coppelius, whom he believes to be the Sandman, a malevolent entity that steals the eyes of children who are awake at night. Hoffmann's unique blend of gothic horror and psychological depth creates a haunting and thought-provoking narrative that delves into the darkest corners of the human psyche. Written in a highly evocative and atmospheric style, 'Der Sandmann' is a masterful example of German Romanticism, influencing later writers such as Edgar Allan Poe and Franz Kafka.