I own a cuddly tortoise sewn by my mother, which she gave me when I was 7. It has a floral shell, a red underbelly and black felt eyes. Even though I’m notoriously prone to losing things, I’ve managed to keep hold of that tortoise through sundry house moves and even changes of country. My mother died over 30 years ago, so I’ve now lived more of my life without her than with her. I find more comfort in that tortoise than I do in photographs of her, which are now so faded and dated, and emphasize how long she’s been gone. What consoles me is the permanence of the object she made — its unchanging nature, its stolid three-dimensional reality. I’d give up many of my possessions to keep that tortoise, the few exceptions being things that have their own allusive power, like my wedding ring.

The most valuable thing I ever lost, at least in a strictly monetary sense, was a pair of spectacular diamond earrings I won many years ago at a charity ball auction. Though very beautiful, my new clip-ons were heavy and turned out to be exceptionally painful to wear, so tight they made my earlobes throb. I wore them to a formal event in London and found them so uncomfortable I discreetly removed them and stowed them in my evening bag. The following day, having flown back to Scotland, I opened my suitcase and they were nowhere to be found; irrevocably lost.

I put those departed earrings into my new children’s book, “The Christmas Pig,” which is a story of objects lost and found, of things beloved and things unregretted. I made my lost earrings grand and snooty, as befitted objects that demanded the wearer suffer for their beauty. When they reach the Land of the Lost, where the hero must go to rescue his most beloved toy, my earrings are angry that they aren’t treated with the respect they think they deserve. They soon find out that being made of diamonds counts for very little in the strange world where human-made objects go when lost, because a thing’s importance there depends on how much it’s truly loved.

There can be a strange magic in human-made things. Not in all of them: not in plastic bottles or Q-Tips or batteries; but in those that are interwoven with our pasts, with our homes, with our great loves. These are things that have been mysteriously imbued with humanity — our own or other people’s.

The magic of “things” often goes unnoticed until they break or are lost. We have favorite mugs and tea towels, comforting in their familiarity and utility; we treasure the lopsided objects our children made for us in nursery school, and we may still own those toys that soothed us when we were tiny. “The Christmas Pig” was inspired in part by one of those achingly necessary toys without whom sleep is impossible: a cheap cuddly pig around eight inches tall, with a belly full of plastic beans, that belonged to my son, David.

David was so attached to that pig, but so prone to losing it, that I became scared it would one day be lost and never found again. I therefore bought an identical replacement and hid it. David was 3 when he went rummaging in the cupboard where I’d stowed his pig’s twin and took it out, slightly confused. He declared it to be his pig’s brother and kept both of them. They’re both still with us, though their names are different from the pigs’ names in the story. Only David’s habit of hiding his beloved pig, then forgetting where he put it, is taken from real life.

Every writer is asked where ideas come from. It’s a relief to have an answer for once, because more often than not I don’t know — the ideas simply arrive. “The Christmas Pig” sprang from my musings on what it means to be a replacement toy. I’d always wanted to write a Christmas story, and once I’d dreamed the Land of the Lost into being I realized I’d found one at last. Christmas was the perfect backdrop to a tale of loss and love, sacrifice and hope.

Of course, it isn’t necessary to actually celebrate Christmas to grasp that element of the story. Every culture has its sacred, celebratory days when feasts are made and consumed, when the grown-ups are making a special effort, when the whole family assembles, when gifts are exchanged.

“The Christmas Pig” explores a deep attachment to an old object, with all its half-understood associations and meanings, at a time when we’re supposed to be in thrall to acquiring the new. It’s about the journey of a boy, Jack, who has a complicated family life, and is consequently a little lost himself, but who discovers his bravery and deep capacity for love in a strange new world. Of all the books I’ve written, this is the one that made me cry the most, because I was dealing with emotions that run deep in all of us. Loss and change are hard for children, but acceptance of these inevitable parts of life isn’t much easier for adults. There was a particular poignancy in finishing the book (which I began to think about in 2012) during a pandemic that has plunged us all into a frightening new world. “The Christmas Pig” shows how human beings — even small, lost ones — are capable of wonderful, heroic, transformative acts. It’s a story in which hope triumphs over despair and individual acts of kindness bring about huge, positive change.

A very strange thing happened on the day I finished editing “The Christmas Pig.” After emailing the final manuscript to my editor, I set about the mundane job of clearing out a cupboard. Sorting through its items — half my mind still in the story, with Jack and the things that came alive on Christmas Eve — one of the last objects I picked up was a small, nondescript box. It rattled. I opened it.

Now, you might believe this or you might not. I can’t blame you if you don’t; after all, I make things up for a living. Nevertheless, this is the truth: There, twinkling up at me as though they’d just been cleaned, were my long-lost diamond earrings, which I hadn’t seen for decades. How they came to be in that box, in that cupboard, I have no idea, nor can I fathom how they moved house with us without my knowledge. Nor do I understand how they escaped the careful search I made of the evening bag and the suitcase from which they disappeared.

Doubtless there’s a prosaic explanation, though I can’t for the life of me imagine what it is. Sitting on the floor amid the piles of dusty things I’d been sorting, utterly astonished by my discovery, I tried the earrings on again. They were exactly as painful as I remembered.

I’ve decided to sell them and give the proceeds to my charity, Lumos, which works to end child institutionalization. I think it rounds out my earrings’ story rather nicely, to have them return from their long exile humbled, wanting to do some good for children in the Land of the Living. I’ll write a note for the new owner — whose earlobes, with any luck, will be made of sterner stuff than my own — and explain their history, in hopes that they’ll give somebody as much pleasure as their rediscovery gave me.

How many times have I been asked whether I believe in magic? On the day I finished “The Christmas Pig,” for a few shining moments I really did.

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