In Pilgrim, Maggie Stiggle's portrait of Hetty is both beautiful and transformative. It was written entirely from memory in a single sitting with no major edits.

'I am certain that the way an artist like Hetty uses memory is a key to finding peace of mind and clarity of thought, giving us a profound sense of achievement even through the tiniest, most everyday things. Hetty knows that she doesn't need to parachute from the top of a skyscraper to feel that she has achieved something remarkable.

'If we actively work with our memory by doing something as simple as telling a story to a friend or stranger, or cooking a curry from the raw ingredients without a recipe, it helps to keep our mind young, fresh and adaptable, so that we are always learning. The effects on our general health can be near-miraculous.

'Since I first taught children to read, write, paint pictures and play music in a primary school in 1972, I have worked with thousands of children and adults. I can swear with hand on heart that actively developing our memory is every bit as important for children as it is for people approaching old age. It is the only way in which our planet stands a chance of healthy survival.'

Percy Stewart intentionally uses memory-triggers all through the Tunesmith books. He finds food and place memories especially useful, and in Tunesmith, tinsmith, he makes many musical references which will trigger memories for people who lived through the last decades of the twentieth century.

'People who have told me about their experience of reading Tunesmith and Pilgrim have said the same thing...that the books bring back their own memories, including things they thought they had forgotten. Any well-written book will achieve this, building on things which we already know and therefore strengthening our foundations through the whole of our lives. It starts with a parent reading a story to their child, or looking through a book with interesting pictures which have some direct relevance to the child...a book on astronomy, which opens our eyes to the wonders of the night sky if we are fortunate enough to be away from bright city lights, for example.

'You could say that in Pilgrim, Hetty encapsulates this life-giving process.'

'When I sit down to write in the tranquillity of this cottage, with no-one to interrupt my train of thought, it becomes possible to detach my mature self sufficiently to once again see the world through an innocent child's, confused teenager's or foolish young man's eyes. I have clear visual memories of precious, simple events going right back to the beginning of the sixties.

'For example, I can remember buying a home-made ice lolly on a long walk to the park in the autumn of 1960 or 1961.

'I can picture the tiny Fletton-brick, slate-roofed shop, and the huge horse-chestnut trees with conkers fallen on the ground, and the sunshine through the yellowing leaves, the swings, the hot metal of the slide and the combination of red-painted wood and polished steel of some kind of dragon-ride, with a row of seats on its back and a running-board at each side. I remember the discovery of how it was supported on two black steel pillars, with a squeaky hinge hidden inside each end of the dragon's body, which seemed paradoxical to me at that age because I already knew that dragons have four legs. I remember the colour, the shape and the general effect of the lolly, which was my first.

'The stick was in it at an angle and it must have been made in a simple upright mould, much easier to work with than the flat ones we had at home some years later. It was either blackcurrant or dandelion and burdock...that bit is confused by other memories from the same period, coming from my grandmother's house, where there was no fridge right to the end of her life well into this century.

'Thankfully I'm a realist and I know that there's a possibility that the lolly-shop memory could actually be a composite of two or three visits to the park in the summer and autumn, which would explain the conkers on the ground. In reality they might be a later memory, from when I was old enough to play conkers in the school playground years after we moved to the other end of town.

'In retelling this another memory has now surfaced. The understanding of the squeaky hinges was guided by my father, who definitely wasn't in the picture when I bought the lolly, and this seems to confirm that we went to the playground more than once. I even have a sense-memory of going there with my father, and of him pushing us on the swings. I can physically remember getting dizzy and having to get off the swing, because he didn't realise how sensitive my inner ear was to movement...all of this is coming back from the beginning of the sixties, even though on the face of it there is nothing at all remarkable in the events themselves!

'That visit must have been on a Sunday, because my father worked all day Saturday in the Co-op eight miles away. The little lolly shop would have been closed on a Sunday afternoon, because this was many years before Sunday opening rules were changed, explaining why my father wasn't in the lolly-picture.

'What I can say for sure is that the black-painted steel pillars are a conscious adult invention. At the time those pillars were rusty, and I can clearly visualise the new black Hammerite paint from another visit many years later, showing the park to someone else, when the dragon was still there.

'Other than growing very much smaller, the trees and the park had hardly changed. The 'dragon' was actually a cast-iron horse's head with a four-seater body.'

'Perhaps the most interesting bit of this memory-picture is the shop itself. When I went back to the park in the eighties, the shop had been closed for over twenty years. In my memory it was a sweet shop, with jars of liquorice all-sorts and everything else on the counter, which I used in Pilgrim.

'Obviously, this boy's memory was highly selective!

'In reality I'm pretty sure that it sold cans of Heinz baked beans, Morton's marrow-fat peas, Libby's peaches, Carnation evaporated milk and someone else's prunes, as well as tins of ham, Fray Bentos corned beef, newspapers and a few magazines, Players cigarettes and a few household essentials, because it was the only shop at that end of town. I wasn't very good at opening the ham tin and still have the scar on my left thumb to prove it.'

'Both at home and at school, we weren't bombarded with ephemeral information, nor were we forced to make too many choices. Children's television in our house in the mid-sixties was limited to Blue Peter, Jackanory and Crackerjack. Newsround, Robinson Crusoe and Tom and Jerry only came into our house later on, by which time we were old enough to realise that some of the other cartoons were total garbage, churned out to a predictable formula.

'What we did learn had more chance to stick, giving us a secure foundation of useful knowledge on which many of our era have continued to build for the rest of our lives.'

'Buried beneath my own foundations, anything I write now will have been coloured or guided by things which we were taught in those early years, though of course I do now realise that Winne the Pooh wouldn't really have been able to float up to a bee's nest high in a tree, lifted by a big blue balloon. For a start with, Christopher Robin's pop-gun had its cork tied to the barrel with a string, but at that age my mind was stuck on the string being too short to reach the balloon, and I painted a big picture of it which went onto the classroom wall.

'Nowadays someone might be inclined to psychoanalyse the balloon and pop-gun as an expression of male sexual fantasy and domination, but thank goodness we were allowed to simply enjoy the story, as children who might one day become extremely healthy, kind, loving adults.'

'Memory is so useful, especially when we think we have forgotten something. It's one of the foundations of human creativity, something which you will see time and time again with young children learning to write stories and paint pictures.

'As adults we fill our heads with clutter and then some of us marvel at the fact that illiterate societies were able to memorise huge narratives, that an Australian Aborigine could find water in tens of thousands of square miles of desert.'

So much of what seems supernatural or merely the whimsical invention of a a writer can actually be perfectly true. In these three books the writer leaves it to the reader to decide. 

Time flies