Riordan, Rick. <br/><br/>
Percy Jackson and the Olympians, Book Four: The Battle of the Labyrinth (Cover May Vary). 

 - 400  p. 
<br/><br/> Percy Jackson and the Olympians, Book Four: The Battle of the Labyrinth (Cover May Vary) by Rick Riordan (2009) 
<br/><br/><label>ISBN: </label>1423101499