DER SANDMANN (1816) is Hoffmann's best known novella for a variety of reasons. Nathanael's teetering on the edge of madness, Clara's sober rationality, the terrible secret of Olimpia, and Coppelius's mysterious machinations have all fascinated readers, critics, and psychologists. It is hardly surprising that the volume of secondary literature on the story has now reached such proportions that it is difficult to present a concise overview of all that has been written. Some critics have even gone so far as to claim that the story resists interpretation altogether:

Despite this claim, it is possible to discern a number of distinct critical trends. First, there are those who have isolated particular motifs in the story: the symbolism of the eye; the opposition between madness and sickness, between hot and cold; and the idea of the human robot. Second, there are those critics who concentrate on the story's formal structure, focusing on the narrator and the different levels of narration. But for all their diversity, most of these approaches can be categorized by the way that they deal with two key questions: (a) is Nathanael driven mad by his own unfettered imagination, or are there other mysterious forces at work? And (b), is Clara to be seen as a positive or a negative figure in the story?