Teachers are important in people's lives, often far more important than they realise. This cliche has been brought home to me by the recent death of my mother in her late 80s, after a long and fulfilled life.
She taught geography at various schools, state and private, in England and Wales for 40 years, before retiring with my father to a bungalow outside Cardiff to be nearer their children and grandchildren.
One day, she received a telephone call from a man whom, it emerged, she had taught 50 years before in the English Midlands during the war. He had used the internet to find all the Mary Prices in the UK and was systematically ringing them to find her. It took him six calls because, knowing my father was Welsh, he had started with Welsh numbers.
In December 1946, when she had left the school to marry my father and make a new life teaching in London, a gang of sixth-formers had insisted on seeing her off on the train. This was one of those boys, now a retired successful businessman.
Over the following years a stream of people came and visited their old geography teacher. Others wrote long letters describing what they had done and where they were now.
One pupil had set up a crockery manufacturing company, so personalised mugs arrived at the bungalow. Another had ended up designing postage stamps for the Channel Isles - examples were on the envelope he used.
One of them had become an eminent academic. He is now an emeritus professor at one of the most prestigious science institutes in the United States. He came from Georgia to visit her and presented a copy of his bestseller, Diffusional Mass Transfer.
He developed the technology which makes kidney dialysis machines work, as well as cooling systems for rockets and the basis for much of modern chemical engineering. I had to find a copy of my mother's Modern Geography of Wales to send to him - one author to another.
In a letter he sent to me after my mother's death, he wrote: "Her teaching style was so effective that I tried to emulate it during my own professional duties."
I look at her grandson, my son who started as a newly-qualified maths teacher at a south Wales comprehensive in September, and wonder who will be contacting him at the end of the 21st century.
Martin Price is chair of governors at St Richard Gwyn Roman Catholic high school, Barry