With that in mind, it makes sense that the original intended audience for these books was children age 8 to 12. However, as the series continued, the characters in the Harry Potter world aged, and so did the children who were reading the series. By the time the last book was published—ten years after the first book was published—the series had garnered a huge, international fan base full of people of all ages: not just children.
The kids who had started off reading this series in elementary school had certainly grown up, but they weren't the only adults who were invested in this series. It had captured the hearts of young adults all across the world, whether they had grown up reading these stories or not. Parents and grandparents were invested in the story of Harry Potter and his friends. But why were they so drawn to this story in the first place?