sentences:  Is (novel)
  
  Is, known in the United States as Is Underground, is the eighth book in the series of novels by Joan Aiken normally called the Wolves Chronicles and sometimes the "James III" sequence.Where previous books have followed the characters Bonny, Sylvia, Simon, and the street-urchin, Dido Twite, this marks the first appearance of Dido's sister Is Twite as the protagonist.