Book 4, the fourth 13-episode "season," of Avatar: The Last Airbender spinoff Legend of Korra will begin streaming on Friday, October 3rd  New episodes will be released each Friday.     

Nickelodeon stopped airing the show on TV in the middle of season 3 (see "The Non-Cancellation of 'Legend of Korra'"), but continued to release new episodes online, where the bulk of its viewers were seeing the show. 

Dark Horse Comics is releasing a merch range tied to Korra (see "Dark Horse to Produce 'Korra' Merch"), and will release a second art book tied to the animated series this month.