In 1978, fresh out of Oxford, Timothy Garton Ash set out for Berlin to see what he could learn from the divided city about freedom and despotism. As he moved from west to east - from Berlin glamour to Berlin danger - the East German secret police, the so-called Stasi, was compiling a secret file on his activities, monitoring his Berlin days and nights and tracking his growing involvement with the Solidarity movement in Poland.

Fifteen years later, with the wall torn down and Berlin now unified, Garton Ash visited Stasi headquarters to find his file. The thick dossier he was given forms the basis for this real-life thriller in which he traces and confronts the German friends and acquaintances who informed on him, and the officers who hired them. Behind Stasi reports of suspicious meetings we discover the love affairs, friendships, and formative intellectual encounters that actually occurred.

And behind a baffling web of lies, half-truths, and forgotten stories we find a forty-year-old man spying on his younger self.