Book One: Water is the first season of Avatar: The Last Airbender, an American animated television series produced by Nickelodeon Studios. Created by Michael Dante DiMartino and Bryan Konietzko,[3] the first season premiered on Nickelodeon on February 21, 2005.[1] It consisted of 20 episodes and concluded on December 2, 2005.[2] The series starred Zach Tyler Eisen, Mae Whitman, Jack DeSena, Dante Basco, Dee Bradley Baker, Mako Iwamatsu, and Jason Isaacs as the main character voices.