I am writing this from a place called the Island of the Deer. Many people know this island from afar, from its three almost-conical mountains, the Paps of Jura, but not that many set foot on it. In spite of its considerable size, Jura is practically empty. There are barely 180 people here, which means that the population is greatly outnumbered by the ubiquitous red deer, and by the sheep, and the cattle too. In fact, by everything.

From where we are staying, in the Distillery Lodge, we can look out over Craighouse Bay to a small strip of islets that stand between Jura and the Scottish mainland . One of these islands bears the Gaelic name of Eilean Diomhain, which translates as Useless Island. It is rather beautiful, as everything is here, but then when you are struggling for a living, fishing or collecting kelp, or surviving the depredations of clan warfare, your naming of places may be grimly functional.

The Distillery Lodge is attached to the island's only distillery. The more fertile island of Islay, which lies just a narrow channel away, boasts a roll call of distilleries, but Jura only has one, and a small one at that. Islay whisky is regarded as a classic island product, some of it so peaty, so aromatic, that it reminds one of the medicines of childhood. Cough syrup. The iodine mixture dabbed on the cuts and scrapes of the playground. Yes, say its enthusiasts, that's exactly it. And we love it.

Jura whisky is a different matter. Their main single malt is smooth and easy on the palate, rather akin to a Speyside, and evokes a whole range of non-medicinal associations. I sampled a dram from a cask in the distillery that had notes of banana rum in it. And mint and pepper too. One can, in fact, find all sorts of things in the nosing of this magnificent Jura single malt.

Together with my wife and one of my daughters, I am being looked after by Lizzie Fletcher, the younger daughter of the laird of Ardlussa, a remote estate further up the island. When we arrived, tired from the trip from Edinburgh, she was already in the kitchen, clad in a blue apron that inspired immediate confidence. There is something about the way a good cook stands; they are always relaxed, surveying what is going on, flicking a wrist to chop something here, deftly turning the heat down there. You can tell that they know what they are doing, and that they love it. Auden wrote something about that, about how one could tell from the look on a person's face that they loved their job. With cooks, it's the posture that reveals everything.

Lizzie had prepared a meal for us. There are scallops with fried pancetta to start with. These scallops are straight out of the sea, harvested by a man in the village who dives for seafood in good places that he discovers along this empty coast. Then we move on to langoustines that are again barely out of the water. The important thing about such people is that they are brought up with the produce they use. Lizzie's father's estate is one of the great deer-stalking estates of Scotland and Lizzie knows how to deal with venison. And if you know the fishermen too, and have been brought up with them, then you have a real feeling for the ingredients you use to work your magic.

Food reminds us of something we tend to forget: we rely on people who work the land, whether it's land on our doorstep or land far away. In urban Scotland, the memory of the land is not altogether lost. A surprising number of people in Scotland have a link with a farm somewhere that was severed only a generation or two ago. In my own case, the link was broken with my grandfather. His father had been a Highland sheep farmer, but my grandfather, and his brother, went off to Edinburgh to study medicine. I am not sure whether they took with them supplies of oatmeal, which is what students used to do when they left the farm to study in places like Glasgow or Aberdeen. The Scottish universities used to have a special holiday called Meal Monday, which was meant to allow students to return to the farm to replenish their sack of oatmeal. That holiday was still celebrated some 30 years ago, when I was a student, although nobody used it to fetch oatmeal.

But we did eat porridge, which I suspect today's students do not. I was brought up to have porridge for breakfast by my father, who had been raised on it in Scotland, but who went out to Africa in the early 1930s and never gave up on porridge. We lived in what was then Southern Rhodesia, and our diet was a typical British colonial one, stodgy and dull. As children we never had anything fancy to eat, apart from the home-baked cakes and biscuits which emerged from the kitchen in large trays: coconut ice (in pink and white layers), gingerbread, crunchie biscuits. It was a recipe for the ruining of teeth, especially in pre-fluoride days. And it resulted in painful visits to the dentist, when the holes in the teeth would be filled with large fillings. I remember being taken to a dentist who had a pedal drill; the bit was driven by an elaborate system of pulleys powered by the dentist's pedalling on something like a treadle sewing machine. It should have cured a sweet tooth, but it did not.

But it was not all sugary and unhealthy. Our main meals at home were reasonably balanced, even if they did not vary a great deal. Lunch and dinner both had three courses, to which families sat down. My family consisted of my parents, my three sisters, and me. We all lived in a house on the edge of Bulawayo, the country's second city, where my father was a public prosecutor in the courts. It was not a very exciting life, although I suppose the setting was fairly exotic by most standards. It was a bit like living in Perth, Australia, or colonial Singapore, but not quite as sophisticated.

At dinner Brown Windsor soup would be followed by something like tripe and onions (which the very mention of today disgusts most people to the point of revulsion, but which I would still enjoy, if I ever saw it). There was a lot of boiled pumpkin and gem squash. Salads, if served, were very unimaginative, and usually just lettuce and tomato, undressed. We never saw olive oil; indeed I first tasted an olive in my very late teens. That, I expect, was the experience of many who grew up in the Fifties and early Sixties, out there and elsewhere. There was not very much dietary exotica, and because of the divided nature of the society we never really ate African food. We were fairly ignorant, I'm afraid, of how most people had to live.

As children we yearned for ketchup, a great treat being a tomato sauce sandwich. As a boy I used to eat raw bacon covered with this tomato sauce. I thought that wonderful. I also ate sugar sandwiches, which were very easy to make, consisting of two slices of white bread spread with butter, on which sugar would be sprinkled. Tomato sauce, though, was to be eaten in moderation, we were told. The reason for this was my mother's belief that consumption of this sauce by children led to what she called juvenile delinquency.

Although my father did not cook, he was in charge of breakfasts in the bush. When we lived in Bulawayo in my young teenage years we used to go out to a range of hills to the south, the Matopos, and have Sunday breakfast made on a wood fire at the bottom of one of the curious granite outcrops that make up that achingly beautiful bit of the world. Breakfast was eggs and bacon, of course, with tomatoes and fried bread for good measure. What is it about wood smoke that adds to the deliciousness of otherwise ordinary fare? The slightly sharp taste, presumably, that stimulates the smoky bit of the palate (if there is such a part).

Those breakfasts are my idea of celestial food, the menu served in heaven. I still come across it from time to time. Last year we breakfasted on the beach in a tucked-away bit of Kirkcudbrightshire, in south-west Scotland. A fire was made of driftwood and we had not only eggs and bacon but that most tempting morsel that my wife was taught to make as a GirlGuide all those years ago - fried Marmite sandwiches. These are delicious at the best of times, but infinitely more so when cooked on a wood fire.

I did not learn to cook as a boy. There may have been a boy scout badge in those days for competence in the kitchen, but neither I nor my friends would deign to do that one. I wish that we had. I also wish that some of the things available to modern boys had been available to boys in those days. Sewing, for example. Typing. Feelings. As a result of this lack, many males of my generation were quite useless in the kitchen, and had to learn how to look after themselves only when they first embarked on their bachelor existence.

I spent my entire childhood in Africa. The rest of my life, or most of it, has been spent in Scotland, although I have lived for short periods elsewhere. I spent a year in Northern Ireland, where I had my first job as a university lecturer at Queen's University. I returned to Scotland and led a bachelor existence for the next eight years or so. Towards the end of that period in my life, I went to live for six months in Swaziland, where I lectured in law at the university. It was a return to Africa and the beginning of my life as a writer. My first book, a children's book called The White Hippo, had just been published. It was while I was in Swaziland that I saw my first review, in the Times Literary Supplement. The reviewer said: 'There are some inept attempts here at fine writing.' That was me put in my place, but I nonetheless sat in my house at Kwaluseni by night and wrote my next children's book, The Perfect Hamburger. I don't like hamburgers, and never have, but I know that children do, and the book is still in print after25 years. Over the next 15 years I wrote quite a number of children's books which have a food motif - The Ice-Cream Bicycle, The Popcorn Pirates, The Spaghetti Tangle. I have discovered that children like nothing better than to read about things they can put into their mouths and eat. Young readers are very oral. In fact, now that I come to think of it, middle-aged readers are very oral too. During those student and bachelor years in Edinburgh, I learned the basics of cookery through trial and error. It was at this time that there occurred that extraordinary sea change in British eating habits that made enthusiastic Mediterranean chefs of so many previously unskilled young men.

For me, the seminal experience was a spell as a postgraduate student in Italy, in Siena. Pizzas had arrived by that time in Britain, but nothing like the thin-crust pizzas which were cooked in a small hole-in-the-wall pizzeria close to the student house in which I lived. I used to go there for breakfast on those already hot mornings and buy a square of pizza which a hirstute, sweating baker cut from vast freshly baked sheets of it. He used secateurs to do this, and the pizza was then slid skilfully on to a piece of greaseproof paper and served with a small glass of raw Tuscan wine. After the initial shock of seeing people drinking wine for breakfast, I adapted, and subsequently made further forays into other, more adventurous forms of Italian cuisine.

That was in 1974. I fell in love with Italy then - it is a common enough love affair, and for many from our pallid northern cultures it is a love affair that lasts a lifetime. To begin with, though, I was not a very successful Italian cook. When I had people round for dinner, I tended to make the same thing, and not very well. Risotto was the standby, but not, I confess, made with proper Arborio rice. The results, I think, were not terribly good, and indeed they led on one occasion to an actual letter of complaint from a friend. He did not write in jest; he was serious. 'I notice that you served only two courses,' he wrote. 'Rice and then chocolate biscuits. There is no excuse for that, which is mean, even by your standards.'

This letter was much admired by other friends, and for a brief period it spawned a number of tongue-in-cheek imitations. Alan Watson, then professor of Roman law in Edinburgh, wrote after he and his wife had been for dinner in my flat: 'We notice that you served only one sort of wine, and Italian at that. We suppose you think that goes with Italian food.' And then another friend wrote to the great Ken Mason, then professor of forensic medicine and famous not only for his pioneering work on the pathology of aircraft accidents but also for his lethal champagne cocktails: 'I enjoyed your champagne cocktails, but I feel that I must complain about their strength. After the party I had barely travelled 20 feet before I fell off my bicycle, an occurrence for which I must hold you responsible.'

Today my cuisine of choice is Italian, and the diet we eat at home would not be out of place in a typical Italian household. Over the years I have made many Italian friends, and one in particular, an engaging professor of criminal law, Alberto Cadoppi, introduced me to the finer points of Parmesan cheese. The cardboard-like grated cheese which one buys in supermarkets has very little to do with the superb, slightly crumbly cheese which comes from the region around Parma and Reggio Emilia. Whenever we visit Alberto he takes us to one of the factories in the rich Emilian countryside. I buy it in large segments and carry back to Scotland sufficient quantities to last six months. A few favoured friends get a piece each, the rest is rationed out to last until the next trip.

Being a novelist does not mean that one has any special insights into life. But writing does at least make one think about the various associations that make up the texture of our personal world. Food associations, like associations of place, evoke memories of moods, of people, of moments of personal significance. Lin Yutang expressed this famously in his observation that patriotism is nothing but the love of the things one ate in one's childhood - an unduly reductionist sentiment, certainly, but one which contains a grain of truth.

I introduce food into the story of the lives of my fictional characters for several reasons. What the characters feel about food can tell one a lot about them - about their past, about their personality, about their aspirations. But, in a more prosaic way, the sharing of food provides such a useful backdrop against which things can happen. Mma Ramotswe, the heroine of my No 1 Ladies' Detective Agency series, is described as a lady of traditional build. This means that she is large, and her comfortable figurecomes from the fact that she enjoys her food. In the most recent novel in the series, Blue Shoes and Happiness, she embarks on a diet, but fails, as we know she will, right from the beginning. The final temptation that gets her off the diet is a slice of Mma Potokwani's rich fruit cake, the same cake which that formidable matron uses to manipulate Mr JLB Matekoni.

On the subject of fruit cake, I have discovered, to my surprise, that a large segment of the American public does not like it. Many of my American readers have asked me why the characters in the books eat fruit cake when there are so many more attractive alternatives available. They then explain that they can stand neither the sight nor smell of such cake which they clearly consider to be a vaguely un-American thing to eat; not quite as bad as Marmite, in their eyes, but almost. The British, of course, know better, as do the people of Botswana. The woman on whom I based the character of Mma Potokwani, a splendid lady - also of traditional build - was in real life a great baker of fine fruit cake which she offered visitors to the orphanage of which she was the matron. That matrons should be of generous figure and also the bakers of heavy cakes seems to me to be entirely appropriate.

The people of Botswana - the Batswana - have a taste for meat, as most people do in that part of southern Africa. They love their cattle, and the surest sign of wealth is the ownership of a good herd. Meat is usually roasted or grilled and served with sorghum or with whatever vegetables are available, sometimes the ground melons that grow so well in the dry land on the edge of the Kalahari. But some of them also keep ostriches. There have been cases of ostrich rustling in the south, which have now cropped up in the books. There is something irresistible about the idea of ostrich rustlers.

There are regular scenes in the books where Mma Ramotswe and her assistant, Mma Makutsi, sit in their office, drink redbush tea, and eat cake. Some people take me to task for this, but I suspect that they do not realise just how many people want to read about precisely these things. And it is not for entirely escapist reasons that people visit and revisit such scenes; the small rituals of life - the drinking of tea and the eating of cake - are really big things in disguise. We need to sit down at the table with others while discussing with them the small, and the major, events of our lives. These activities anchor us in our relationships with others and establish patterns in our lives.

I find this in my own life. I live in a Victorian house in Edinburgh and spend a lot of time in the kitchen, which has an Aga to keep us warm. My wife is a superb cook, which she manages to be in spite of heavy commitments as a general practitioner. We like to have just a few friends for dinner - usually just two - and we like to talk about the small things of the day. That is my greatest pleasure in a life which takes me off all over the world, on more-or-less constant tours, meeting vast numbers of people and living in soulless hotels. For a lot of my time away I find that I am actually somewhat lonely and long to be back, in the kitchen, with just a few friends, listening to the gossip.

My ideal dinner party guest, I think, would be WH Auden. I should specify the early Auden, though, not the late Auden. I had a friend who was fortunate enough to have dinner with Auden a year or so before the great poet died. He said that Auden spent most of the time complaining about the soup. Perhaps he should have saved that for a letter of complaint.

· Love Over Scotland by Alexander Mccall Smith (Polygon, £14.99hb), the third book in the 44 Scotland Street series, is out this month. Friends, Lovers, Chocolate (in The Sunday Philosophy Club series) is now in paperback (Abacus, £6.99)