Rules of Spycraft (2009) [pdf]
For reasons I can’t quite remember, in the late 90s I once had a drink at an army club in London. I’m not very army at all, so it was not somewhere I’d expect to go as a rule. My overriding memory was an old paratrooper at the bar telling me in a very old-fashioned and serious voice, “never be a spy”. I must have not been 20 at the time, and it seemed like very good advice.