The term "middle grade" refers to a category or genre of literature that is typically aimed at readers between the ages of 8 and 12 years old. These books often feature younger protagonists, engaging storylines, and themes that are appropriate for this age group while still providing some level of intellectual challenge and emotional depth. Middle grade novels can be found in various genres such as fantasy, adventure, mystery or historical fiction, among others. They typically have a reading level between 2nd to 4th grade, with shorter sentences, simpler vocabulary, and more illustrations than books for older readers.