I want to know why the universe exists, why there is something greater than nothing.

Or in other words, why does disorder increase in the same direction of time as that in which the universe expands?

Thirty years ago I was diagnosed with motor neurone disease, and given two and a half years to live. I have always wondered how they could be so precise about the half.

Only time - whatever that may be - will tell.

I have sold more books on physics than Madonna has on sex.

For millions of years, mankind lived just like the animals. Then something happened which unleashed the power of our imagination. We learned to talk and we learned to listen.

We find ourselves in a bewildering world. We want to make sense of what we see around us and to ask: What is the nature of the universe? What is our place in it and where did it and we come from? Why is it the way it is?