After multiple books and films about his decision to leak the biggest cache of top-secret documents in history, whistleblower Edward Snowden is set to tell his side of the story in a memoir, Permanent Record.

Out on 17 September, the book will be published in more than 20 countries and will detail how and why the former CIA agent and NSA contractor decided to reveal the US government’s plans for mass surveillance around the world and in the US – which included monitoring phone calls, text messages and emails.

UK publisher Macmillan said the book would see him “bringing the reader along as he helps to create this system of mass surveillance, and then experiences the crisis of conscience that led him to try to bring it down”.

Snowden’s story has been already been tackled on film and in books. He was portrayed by actor Joseph Gordon-Levitt in the Oliver Stone film Snowden, which was adapted from Guardian journalist Luke Harding’s book The Snowden Files. Journalist Glenn Greenwald, the source to whom he leaked his explosive story, recounted in his memoir No Place to Hide how he went to Hong Kong in 2013 to meet an anonymous source who claimed to have evidence of government spying. Snowden was also the subject of the 2014 documentary Citizenfour, directed by Laura Poitras, and the 2016 play Wild, a fictionalised take on his story.

“Edward Snowden decided at the age of 29 to give up his entire future for the good of his country,” said Macmillan chief executive John Sargent. “He displayed enormous courage in doing so, and like him or not, his is an incredible American story. There is no doubt that the world is a better and more private place for his actions.”