Question: is there a book 4 of avatar the last airbender

Answer: Yes, Dark Horse published a graphic-novel series by Gene Yang that continues Aang's story after the Hundred Years' War. Avatar: The Last Airbender -- The Promise, published in three volumes in 2012, explores the fate of the Fire Nation colonies that become The Legend of Korra's United Republic. A second set of three comic books, Avatar: The Last Airbender -- The Search, focuses on Zuko and Azula, and the fate of their mother Ursa. The third set, Avatar: The Last Airbender -- The Rift, shifts the focus to Aang, the creation of Republic City, and Toph's relationship with her family. The Rift was followed by Avatar: The Last Airbender -- Smoke and Shadow about a resistance force in the Fire Nation against Firelord Zuko, who at the end of the original series assumed the throne. The fifth graphic novel was Avatar: The Last Airbender -- North and South, which follows the events of Smoke and Shadow and is about Katara and Sokka returning to the Water Tribe to see various changes to their homeland. The next planned graphic novel is titled Imbalance and is planned to be released in October 2018. The series explores the emerging conflict between the benders and non-benders that becomes the center for the conflict in the first season of the sequel the Legend of Korra. Unlike the previous five books it is will not be written by Gene Yang.