There'd never been a more advantageous time to be a criminal in America than during the 13 years of Prohibition. At a stroke, the American government closed down the fifth largest industry in the United States - alcohol production - and just handed it to criminals - a pretty remarkable thing to do.

It is a slightly arresting notion that if you were to pick yourself apart with tweezers, one atom at a time, you would produce a mound of fine atomic dust, none of which had ever been alive but all of which had once been you.

Every atom you possess has almost certainly passed through several stars and been part of millions of organisms on its way to becoming you. We are each so atomically numberous and so vigorously recycled at death that a significant number of our atoms-up to a billion for each of us, it has been suggested-probably once belonged to Shakespeare. A billion more each came from Buddha and Genghis Khan and Beethoven, and any other historical figure you care to name.

... it occurred to me that never again would he be seven years, one month and six days old, so we had better catch these moments while we can.

Human beings would split the atom and invent television, nylon, and instant coffee before they could figure out the age of their own planet.

But I got a great deal else from the experience. I learned to pitch a tent and sleep beneath the stars. For a brief, proud period I was slender and fit. I gained a profound respect for the wilderness and nature and the benign dark power of woods. I understand now, in a way I never did before, the colossal scale of the world. I found patience and fortitude that I didn't know I had. I discovered an America that millions of people scarcely know exists. I made a friend. I came home.

If you go out on the Appalachian Trail, you have to bring so much more equipment - a tent, sleeping bag - but if you go hiking in England, or Europe, generally, towns and villages are near enough together at the end of the day you can always go to a nice little inn and have a hot bath and something to drink.