'Edward Snowden was apprehensive of foreign forces seeking his files'

Edward Snowden was alert to the possibility that foreign intelligence services would seek his files, and was determined to prevent this, says a book that tells the story of the man behind the biggest intelligence leak in history.

In "The Snowden Files: The Inside Story of the World's Most Wanted Man," award-winning Guardian scribe Luke Harding recounts the incredible story of Snowden - from the day he left his glamorous girlfriend in Honolulu carrying a hard drive full of secrets, to the weeks of his secret-spilling in Hong Kong, to his battle for asylum and his exile in Moscow.

Harding brings together the many sources and strands of the story - touching on everything from concerns about domestic spying to the complicity of the tech sector - while also placing the reader in the room with Snowden himself.

"As a spy, one of his jobs had been to defend American secrets from Chinese attack. He knew the capabilities of America's foes. Snowden made clear repeatedly that he didn't want to damage US intelligence operations abroad," he writes.

"I had access to full rosters of anybody working at the NSA. The entire intelligence community and undercover assets around the world. The locations of every station we have, all of their missions… If I just wanted to damage the US I could have shut down the surveillance system in an afternoon. That was never my intention," the book, published by Guardian Faber, quotes Snowden as saying.

He puts it in even more vivid terms, when subsequently accused of treachery, "Ask yourself: if I were a Chinese spy, why wouldn't I have flown directly into Beijing? I could be living in a palace, petting a phoenix, by now." According to the author, during the days of debriefing in Hong Kong, Snowden said citizens in countries that recognised whistleblowing and public-interest reporting had a right to know what was going on. He wanted the Guardian and other media partners to filter out anything that was operational and might damage legitimate intelligence activities. These were his conditions and all agreed.

Snowden, a former CIA employee and National Security Agency contractor who fled the US after leaking details of the American government's spy programs, was granted temporary asylum in Russia last year. 

He had broad access to the NSA's complete files as he was working as a technology contractor for the omnivorous US eavesdropping body in Hawaii, helping to manage the agency’s computer systems in an outpost that focuses on China and North Korea. According to Alan Rusbridger, Editor-in-chief, Guardian, what Snowden revealed is important and his files show that the methods of the intelligence agencies that carry out electronic eavesdropping have spiralled out of control, largely thanks to the political panic in the US which followed the terrorist attacks of 9/11.

"His skills are unprecedented. Until the present generation of computer nerds came along, no one realised it was possible to make off with the electronic equivalent of whole libraries full of triple-locked filing cabinets and safes – thousands of documents and millions of words. "His motives are remarkable. Snowden set out to expose the true behaviour of the US National Security Agency and its allies," writes Rusbridger in the foreword.

The book also says how Snowden had an unsuccessful stint with the US military. "His spell in the US military was a disaster. Snowden was in good physical shape but an improbable soldier. He was short-sighted, with -6.50/-6.25 vision. He also had unusually narrow feet," Harding describes.

Then during infantry training he broke both his legs. After more than a month's uncertainty, the army finally discharged him, the book says.