I wrote a novel about the construction of the Berlin Wall (The Story of Henri Tod) in my Blackford Oakes series. I traveled to inspect the wall, submitting to the indignities of Checkpoint Charlie. The near mystical idea of the wall, bisecting the capital of a modern, industrialized country, as if it were the fancy of a Genghis Khan, fascinated me beyond the stark ideological meaning of it. I returned to Berlin after the wall came down, and found...