They say you can tell a lot about people by the books they read, but you can probably tell more about yourself by those that people lend you. A few weeks ago, for example, I met the comedian Susan Morrison. She had come to Inverness by train and had spent the journey reading a paperback edition of The Ghost Map
"Here, you'll enjoy this, " she said, fishing the book from her bag and handing it to me, "it's all about cholera, cesspools and contaminated water in Victorian London. "
"Thanks," I said, "I'll read it, but I'm more of a bubonic plague man, myself. You know, boils and stuff."
Then, in Glasgow last week, my colleague Gareth Hydes handed me Mary Roach's book Stiff. It's all about dead bodies and, well, what happens to them in the hands of medical students, morticians and the people who research car crashes.
I think he had heard me talk about how much I had enjoyed the series Six Feet Under having bought the lot in a box-set frenzy.
Fast forward to Edinburgh last week and another encounter with Susan Morrison, this time in the Spiegelgarden. Again she went fishing into her handbag and this time she pulled out a slim little volume which was essentially a guidebook to the prostitutes of old Edinburgh town. Each lady of the night had a little review attached to her name and location and there was many mentions of "good teeth" or "blackened teeth".
I threw Susan a quizzical glance which she caught easily, converted it into a look of know-it-all smugness and tossed back at me.
"Syphillis, " she explained, "rotting gums is one of the more visible symptoms."
So death, disease and prostitution. Now you know what to get me for Christmas.