I’ve already taken a look at the worldbuilding in Star Wars. Now it’s time to take a look at a fantasy setting that most of us known quite well: Harry Potter
One thing that the Harry Potter series does very well is get the reader into the world in a hurry. By the time Harry arrives at Hogwarts, the reader already has a good sense of the world he is about to experience, and is ready to get dumped in the deep end of the pool.
We first see the intersection of the wizarding and muggle worlds at Diagon Alley, a magical marketplace nestled right in the heart of an unsuspecting London. Arcane merchandise is sold openly because no one but wizards can find it. This is a common theme in Harry Potter. Whenever the wizard and muggle worlds abut, there is something that keeps the muggles unaware of just how close they are to magic.
This idea pops up again at King’s Cross Station, where the muggles are stuck with whole numbers, but wizards go to Platform 9 3/4 to find the Hogwart’s Express.
When Hagrid takes Harry to Ollivanders, we get the first lesson in wizardly spellcasting. Wizards need wands. Wizards wave wands. Wands do the choosing, and the nature of a wand’s choice is highly personal. Later, once we get to Hogwarts, this simple foundation doesn’t need to be repeated in the classroom. The other purchases, such as books and caudrons, round out the idea of what it takes to be a wizard in the Harry Potter universe.
As for the rest of the magic system, it is introduced primarily in two ways: straightforward classroom education, and Hermione. Hermione Granger is not just one of the three main characters of the series, she’s also the window into the “proper” ways of the wizarding world. Despite being muggle-born, Hermione knows everything that Ron and Harry don’t. Ron’s taken it all for granted, growing up around wizards; Harry has been blithely ignorant, thanks to his wizard-hating aunt and uncle. Even as the series progresses, being the studious one, Hermione is always ahead of Ron and Harry in her studies, and thus always able to provide worldbuilding bits of magical knowledge for the reader.
In short, if Ron and Harry had hit the books, the reader wouldn’t have known half of what was going on, because Hermione wouldn’t have had to explain it.
Never underestimate the value of a character’s ignorance in providing information to a reader.
While here and there it’s hinted that certain people, places, or objects are quite old, the Harry Potter timeline starts ten years ago, with the death of Harry’s parents. It can be tempting to infer things from before then, and later volumes get into more backstory that extends to the early lives of Harry’s parents, Snape, and Rom Riddle, at the start there is a snippet from ten years ago and nothing else.
It’s an interesting setup, with whispered conversations behind Harry’s back in Diagon Alley. People know Harry’s life story because it was a pivotal moment for all of them.
The overall impression is of a real world, with a long history overshadowed by an event ten years ago that is central to the plot. First, it takes prominence since Harry has entered Hogwarts, dredging up memories, then later on because of the reemergence of Voldemort. But aside from the pasts of Voldemort and a few key characters, the rest of history is largely window dressing.
So by the time Harry gets to Hogwarts, he’s learned the basic elements of the magic system, where the muggle and wizard worlds meet, and the relevant history that will grow into the plot of the series. He’s also met his two best friends, but that’s not exactly worldbuilding.