I was approaching the age of 40 with a substantial publication record, but had not yet held any position in a chemistry department.

I developed an interest in nuclear magnetic resonance, which was then emerging as a powerful technique for studying molecular structure.

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.

No member of my family was involved in any scientific or technical activity. I was the first to attend a university.

I had to leave Cambridge and take up industrial employment for a period. This was with the Bristol Aeroplane Company. There was little to do there.

I had changed from being a mathematician to a practicing scientist. I was increasingly embarassed that I could no longer follow some of the more modern branches of pure mathematics.

Cambridge in 1947 had greatly changed since 1943. The university was crowded with students in their late 20s who had spent many years away at the war.

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.

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.