7 essays by the author of LoTR
The best-known is "On Fairy-Stories," a discussions of the requirements of believable fantasy. It is not about those "Flower fairies and fluttering sprites...that [Tolkien] so disliked as a child." "A Secret Vice" has implications about programming and programmers.
The title essay ("The Monsters and the Critics") sheds light on the unsatisfactory Star Wars prequels.