Poor Despereaux deals with a great deal of isolation from the very beginning of his life in The Tale of Despereaux. For starters, he's the only survivor of his litter. He isn't like all the other mice at all; even his family doesn't understand his fascination with reading and music, and they ignore him.

Roscuro, the villain of the story, is also an outsider. In fact, the reason he's such a bitter and vengeful character is because he feels as though the princess looked upon him as a disgusting creature when he ventured up to the castle. He's now back down in the lonely dungeon, isolated from the world he wants to be part of.

The author considers isolation to be a very unhappy situation. Fairy tales tend to be full of characters who are alone in the world—friendless or parentless. A famous child psychologist named Bruno Bettelheim thought that this is why fairy tales can be helpful for kids to read. It helps them deal with times they're lonely by showing them characters who feel alone but are able to eventually find happy lives and relationships.