Tolkien attempts, as do many fantasy writers, to engender in his readers a new vision of the world around them, or at least a new perspective. He does this primarily by portraying familiar objects as slightly different from those to which the reader is accustomed. Eagles, for example, serve in The Return of the King not merely as birds, but as very large, sentient birds, able to carry people in flight. Shelob the spider, on the contrary, fascinates the reader not so much for her sentience—which seems limited at best—but for her utter evil and her tremendous size, neither of which is a trait actually common to the spiders with which the reader is familiar. Thus Tolkien forces the reader to re-examine his or her own world with a renewed sense of wonder and inquiry.

Some critics, however, find creatures such as Shelob unconvincing...