The Librarian of The Haunted Library by Brian Yansky

A fun, fast, fantastical read: After an altercation with a clown, I get lost in the woods and find a strange town. When the librarian of the town dies in front of me, I try on his ring. It fits. I’m declared the new librarian by the mayor and townspeople. I get to live in a houseful of books. But I soon learn the job involves more than just tomes and information. In fact, my first assignment is to discover who murdered my predecessor.
In my quest to find the killer, I soon discover that there are many other hidden secrets to the town.