ON the morning of August 13, 1961, the residents of East Berlin found themselves cut off from family, friends, and jobs in the West by a tangle of barbed wire that ruthlessly split a city of four million in two. Within days the barbed-wire entanglement would undergo an extraordinary metamorphosis: it became an imposing 103-mile-long wall guarded by three hundred watchtowers. A physical manifestation of the struggle between Soviet Communism and American capitalism that stood for nearly thirty years, the Berlin Wall was the high-risk fault line between East and West on which rested the fate of ...

In 1978 a romantic young Englishman took up residence in Berlin to see what that divided city could teach him about tyranny and freedom. Fifteen years later Timothy Garton Ash--who was by then famous for his reportage of the downfall of communism in Central Europe--returned. This time he had come to look at a file that bore the code-name "Romeo." The file had been compiled by the Stasi, the East German secret police, with the assistance of dozens of informers. And it contained ...