To be sure, The Lord of the Rings is not a great work of literature to be compared to Cervantes or Dostoyevsky.
The Lord of the Rings is a great work of literature that stands in a league of its own. Superficially it is a child's story to enjoy, but it is woven with so many themes and variations of theme that an adult can read it anew year after year. LotR is filled with wisdom and truth--the truth of fiction. I believe it to be truly inspired.
As a student, I read Cervantes and Dostoyevsky because my profs required it. I read Tolkien because his work compelled me.