In February 2006, while researching this book, Matthew Aid uncovered a massive and secret document reclassification program--a revelation that made the front page of the New York Times. This was only one of the discoveries Aid has made during two decades of research in formerly top-secret documents. In The Secret Sentry, Aid provides the first-ever full history of America's largest security apparatus, the National Security Agency.

This comprehensive account traces the growth of the agency from 1945 to the present through critical moments in its history, from the cold war up to its ongoing involvement in Afghanistan and Iraq. Aid explores the agency's involvement in the Iraqi weapons intelligence disaster, where evidence that NSA officials called "ambiguous" was used as proof of Iraqi WMD capacity, and details the intense debate within the NSA over its unprecedented role, pressed by the Bush-Cheney administration, in spying on U.S. citizens.

Today, the NSA has become the most important source of intelligence for the U.S. government, providing 60 percent of the president's daily intelligence briefing. While James Bamford's New York Times bestseller The Shadow Factory covered the NSA since 9/11, The Secret Sentry contains new information about every period since World War II . It provides a shadow history of global affairs, from the creation of Israel to the War on Terror.