Still, the fogs and darknesses of London comforted me, took me in. I had lost my first lodgings because I screamed in the night. I had been in Afghanistan; I was there no longer.

“I scream in the night,” I told him.

“I have been told that I snore,” he said. “Also I keep irregular hours, and I often use the mantelpiece for target practice. I will need the sitting room to meet clients. I am selfish, private, and easily bored. Will this be a problem?”

I smiled, and I shook my head, and extended my hand. We shook on it.

The rooms he had found for us, in Baker Street, were more than adequate for two bachelors. I bore in mind all my friend had said about his desire for privacy, and I forbore from asking what it was he did for a living. Still, there was much to pique my curiosity. Visitors would arrive at all hours, and when they did I would leave the sitting room and repair to my bedroom, pondering what they could have in common with my friend: the pale woman with one eye bone-white, the small man who looked like a commercial traveler, the portly dandy in his velvet jacket, and the rest. Some were frequent visitors, many others came only once, spoke to him, and left, looking troubled or looking satisfied.

He was a mystery to me.

We were partaking of one of our landlady’s magnificent breakfasts one morning, when my friend rang the bell to summon that good lady. “There will be a gentleman joining us, in about four minutes,” he said. “We will need another place at table.”

“Very good,” she said, “I’ll put more sausages under the grill.”

My friend returned to perusing his morning paper. I waited for an explanation with growing impatience. Finally, I could stand it no longer. “I don’t understand. How could you know that in four minutes we would be receiving a visitor? There was no telegram, no message of any kind.”