Definitely, “The Lord Of The Rings” by J.R.R. Tolkien,

“The Hobbit”is obvious. It is as recognizable as The Trilogy.
a reader’s companion to “The Hobbit “ and “The Lord Of The Rings “, not so much. At least, the thread is how anyone will pick up the Trilogy after skimming or checking out “a reader’s companion….” All these famous people have something to say that may persuade you to leap into the big read.
If you like excellent artwork and journaling, you will use both when using this journal: A Hobbit’s Journal: Being a blank book with some curious illustrations of friends & foes of the Nine Companions.