Here's why:
* Chronologically: The events of "The Hobbit" take place about 60 years before the events of "The Lord of the Rings."
* Characters: Many characters from "The Hobbit," including Bilbo Baggins, Gandalf, and even Gollum, reappear in "The Lord of the Rings," playing crucial roles in the story.
* World-building: Both books are set in the same fictional world of Middle-earth, expanding upon its history, cultures, and mythology.
While "The Hobbit" is often considered a standalone story, it serves as a prequel and introduces key elements and characters that become central to the larger epic of "The Lord of the Rings."