It's a large, multi-level room with towering bookshelves filled with countless magical texts. You can find it in the main castle area of most Lego Harry Potter games.
Here's a breakdown of its locations in specific games:
* Lego Harry Potter: Years 1-4: The library is accessible in the "Hogwarts Grounds" level.
* Lego Harry Potter: Years 5-7: The library is accessible from multiple levels in the "Hogwarts" area.
It's a popular location for collecting studs, finding secrets, and encountering various characters and puzzles!