Former National Security Agency (NSA) contractor Edward Snowden has written a memoir that will be published September 17 by Macmillan Publishers.

The whistleblower leaked thousands of classified documents to journalists Glenn GreenwaldLaura Poitras, and Ewen MacAskill in 2013. He now lives in Russia and is president of the San Francisco-based Freedom of the Press Foundation.

Macmillan said: “In 2013, Edward Snowden, a former CIA agent and NSA contractor, shocked the world when he broke with the American intelligence establishment and revealed that the U.S. government was secretly pursuing the means to collect every phone call, text message, and email ever sent.

“The result would be an unprecedented system of mass surveillance with the ability to pry into the private lives of every person on earth. In Permanent Record, he tells his story for the very first time, 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.”

Edward Snowden Memoir: Macmillan “Enormously Proud” to Publish the Book 

The book itself has been a closely guarded secret.

Titled “Permanent Record”, it will be released simultaneously in more than 20 countries, including the US, Germany and Britain.

“Edward Snowden decided at the age of 29 to give up his entire future for the good of his country,” said John Sargent, CEO of Macmillan Publishers USA.

“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. Macmillan is enormously proud to publish Permanent Record.”

Some 1182 classified documents, including 355 marked “Top Secret” leaked by Snowden remain online. The leaks were deeply damaging to the security community, but seen as a public service by civil libertarians. (They were also leaped on by the security community, with the NSA’s so-called “Ant Catalogue” of hardware and software surveillance tools widely perused for inspiration by pen testers).

Among his revelations: that intelligence agencies had built backdoors into tech companies’ offerings, and were tapping marine fibre optic cables to hoover up vast amounts of web traffic.

Snowden, who would face criminal charges if he returned to the United States, remains a resident of Russia.

See also: EXCLUSIVE: GCHQ, NSA Still Using Punched Paper Tape to Produce Crypto Keys