This young adult novel is difficult to classify under one genre. First of all, Holes is an adventure story. The protagonist, Stanley, is confronted with physically and mentally challenging obstacles that he must overcome – including a life-threatening journey into the desert to rescue a friend in need. This adventure story even makes use of the motif of a treasure hunt, and, of course, we have a clear villain – the Warden, who must also be defeated. There are thrilling sequences that could possibly be frightening for younger children like when, for example, the Warden colors her fingernails with nail polish mixed with her poisonous […] “secret ingredient […] rattlesnake venom” (Sachar 90) scratches Mr. Sir´s face with it.
In addition to this main adventure story, there are, of course, two other intertwining stories from the 19th century that help to provide context, motivation, and meaning to the contemporary characters’ actions. This connection to the past places the novel also within the category of historical fiction: we catch a glimpse of life and society in different eras.
However, Holes goes beyond these two genres as well. Given its puzzle-like narrative structure, in which the reader must piece together the different narratives to understand what the Warden is really after and what Camp Green Lake really is, this novel could also be seen as a mystery or detective novel. The reader takes over the role of a detective and finds out how the characters belong together when reading the book attentively.
Moreover, there are even elements of the fantastical in the novel as well, moments where the reader must suspend his disbelief. We see this in the gypsy subplot and the entire motif of fate and destiny that runs through the novel.