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.

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.

I really enjoy going to a library and spending the day doing research - to me that is the most pleasurable part of writing the science book.

We forget just how painfully dim the world was before electricity. A candle, a good candle, provides barely a hundredth of the illumination of a single 100 watt light bulb.

A world without newspapers or a world where the newspapers are purely electronic and you read them on a screen is not a very appealing world.

America is a great disappointment to me. As I said in one of my books, other societies create civilisations; we build shopping malls.

It was the kind of pure, undiffused light that can only come from a really hot blue sky, the kind that makes even a concrete highway painful to behold and turns every distant reflective surface into a little glint of flame. Do you know how sometimes on very fine days the sun will shine with a particular intensity that makes the most mundane objects in the landscape glow with an unusual radiance, so that buildings and structures you normally pass without a glance suddenly become arresting, even beautiful? Well, they seem to have that light in Australia nearly all the time.