Dora Winifred "D.W." Read is Arthur's little sister. She is four years old in the beginning of the series and turns five in an episode featuring her birthday. She is a middle child of the Read family. She attends preschool and enjoys watching Mary Moo Cow and listening to Crazy Bus much to Arthur's annoyance. She is also known for her many short-lived obsessions and tantrums if these obsessions are not fulfilled. Many of the series' episodes revolve around tensions between D. W. and her brother—she especially enjoys getting him in trouble.