Life with a scientist who is often changing jobs and is frequently away at meetings and on lecture tours is not easy. Without a secure home base, I could not have made much progress.

On my return to Pittsburgh, I resolved to go back to the fundamental problems of electronic structure that I had contemplated abstractly many years earlier.

At the age of 12, I developed an intense interest in mathematics. On exposure to algebra, I was fascinated by simultaneous equations and read ahead of the class to the end of the book.

Life with a scientist who is often changing jobs and is frequently away at meetings and on lecture tours is not easy. Without a secure home base, I could not have made much progress.

Our children were mostly brought up and educated in the Churchill suburb east of Pittsburgh. Each summer, we took them back to England for an extended period.

I abandoned chemistry to concentrate on mathematics and physics. In 1942, I travelled to Cambridge to take the scholarship examination at Trinity College, received an award and entered the university in October 1943.

I am delighted to have had students, friends and colleagues in so many nations and to have learned so much of what I know from them. This Nobel Award honours them all.