Compare Wiesel’s and Spiegelman’s choice of genre for their books.
Both chose genres that present a true story of the Holocaust as one experienced it.
The genre both authors chose is memoir as their stories depict a specific event in their lives or someone else's.
Elie Wiesel narrates his experiences as a concentration camp prisoner, whereas Art Spiegelman narrates his father's experiences. Both authors present true stories set in the Holocaust, and specifically on concentration camps.