The Snowden Files: The Inside Story of the World’s Most Wanted Man, by Luke Harding. Guardian Faber Publishing RRP￡12.99/Vintage RRP$14.95, 352 pages

First WikiLeaks and then Edward Snowden – such has been the tsunami of leaks from America’s national security state in recent years, it sometimes feels like there is nothing left to know about how Washington’s diplomats and spies go about their business. The revelations from Snowden, a contractor for the National Security Agency, the omnivorous US eavesdropping body, have far surpassed the initial state department document dump released by Julian Assange.

Not only are Snowden’s documents classified at a much higher level of secrecy. He has unveiled as never before the intimate architecture and entrenched networks of the most secretive postwar institution, the “Five Eyes” intelligence alliance binding the US with the UK, Canada, Australia and New Zealand. Snowden’s documents have disclosed so much about its operations, from the national leaders bugged to the mind-boggling masses of data trawled in search of terror targets, that the extraordinary new material still pouring out is losing its ability to shock.