“One day in September 1939, not long after war was declared and Sipo became part of the RSHA—the Reich Main Security Office—I went to see General Heydrich at his office in Prinz Albrechtstrasse. I told him I was wasting my time and asked his permission to put in my papers. He listened patiently but continued to write for almost a minute after I’d finished speaking before turning his attention to a rack of rubber stamps on his desktop. There must have been thirty or forty of these. He picked one up, pressed it onto an inkpad, and then carefully stamped the sheet of paper he’d been writing on. Then, still silent, he got up and closed the door. There was a grand piano in his office—a big black Blüthner—and, to my surprise, he sat down in front of it and started to play, and play rather well, I might say. While he was playing, he shifted his large arse on the piano stool—he’d put on some weight since last I’d seen him—and then nodded at the space he’d made to indicate that I should sit beside him.

“I sat down, hardly knowing what to expect, and for a while neither of us said a word as his thin, bony, dead Christ hands rippled over the shiny keyboard. I listened and kept my eyes on the photograph on the piano lid. It was a picture of Heydrich in profile, wearing a fencer’s white jerkin and looking like the sort of dentist you might have nightmares about—the kind who would have pulled all of your teeth to improve your dental hygiene.

“Kuan Chung was a seventh-century Chinese philosopher,” Heydrich said quietly. “He wrote a very great book of Chinese sayings, one of which is that ‘even the walls have ears.’” Do you understand what I’m saying, Gunther?”

“Yes, General,” I said, and, looking around, tried to guess where a microphone might be hidden.

“Good. Then I’ll keep playing. This piece is by Mozart, who was taught by Antonio Salieri. Salieri was not a great composer. He’s better known to us today as the man who murdered Mozart.”

“I didn’t even know he’d been murdered, sir.”

“Oh yes. Salieri was jealous of Mozart, as is often the way with lesser men. Would it surprise you to know that someone is trying to murder me?”

“Who?”