I've never met Rosemary Shrager, but I'd very much like to. Her beaming generous face shines out of the cover of Rosemary: Castle Cook, clear blue Scottish sea behind her and a tray of shellfish in her hands. The author runs a cookery school on the Isle of Harris and from these pictures it looks like a warm, comfortable escape from your worlds of stainless steel and an absence of natural light. Am I suggesting a return to school? Perhaps, for if there is one thing this book shouts louder than anything else it is the need to focus on ingredients.

We keep trying to guess what the next food trend is going to be, but my own prediction is there won't be one. We have developed, evolved, been exposed to too much for an 'Italian style' revolution to hit us again. What will happen however, is a growing awareness of ingredients, by both chefs and the public. In this we are only moving in the way America has already gone. You don't get roast salmon there, it is "roast line-caught Shellfish bay salmon".

In the land of Rosemary Shrager everything is wild, fed on the Atlantic-washed Isle of Harris in most cases, sourced from nearby if not. What Scotland lacks in warm sunshine it more than makes up for with a varied weather pattern producing some of the best ingredients in the world - think grouse and venison, lobster and crab, lamb and beef.

What use is this to me? I hear you ask. Most of this product is available country wide, either direct from the producers or via one of the growing band of specialist suppliers like Heritage Foods based in Bristol.

Ms Shrager's book focuses on how wonderful simplicity can be. Her scallops arrive in the shell and still alive, pulsating as she prepares them, either to be seared and served with rocket and red pepper salsa, or fashioned into a mousseline, or combined with egg noodles and ginger and baked in a paper bag - she is nothing if not versatile, Ms Shrager.

Are some of these recipes a little old fashioned I couldn't help wondering. In her introduction Ms Shrager states her style as being "based on classical French tradition with my own personal twist". Her mentors are Pierre Koffmann and Jean-Christophe Novelli, two chefs who may, over the last few years, have fallen into the unfortunate category of having been usurped by more media-friendly, more of-the-moment practitioners. Fear not I couldn't help thinking as I read more, everything comes full circle and while seafood feuilletes may sound old-fashioned, it looks and reads as a delight.

Ms Shrager is not afraid of crossing continents, yet there is a more assured hand with the traditional dishes. Wild salmon with sorrel and courgettes for example, which may sound straightforward but how often do you find sorrel on restaurant menus? Not often enough in my view. Her twist comes in dishes like smoked haddock lasagne, sole with spinach tortellini, or monkfish with ink fettuccine, caper and rosemary sauce. For more Eastern-inspired dishes, look to the likes of Oriental sole, lettuce-wrapped fillets of fish with a mushroom duxelle and served with deep-fried leeks and a soy and ginger-infused sauce.

Amhuinnsuidhe Castle (the name means sitting on the river in Gaelic) is pretty remote and the emphasis of Ms Shrager's school is on using the local ingredients to best effect, as well as indulging in the non-urban, unspoilt and rather unique environment. The pictures in the book, by Christopher Simon Sykes, highlight the unique light of the Western Isles. The food photography lacks definition in places, but conveys the spirit of the food well.

Classics like oxtail are covered, while more traditional dishes like a saddle of lamb stuffed with kidneys and spinach are like dipping into a rather juicy yesteryear. What a welcome change it would be to see something like this in place of the more mundane roast rack of lamb. I may sound old-fashioned but too often I find myself eating restaurant dishes I could easily prepare and do. Short-order cooking is just what you need arriving home after a busy day. Eating out should allow access to those pleasures you do not normally have time for. A stuffed saddle of lamb is a dish I'd travel to.

If there were an honorary title, 'Mere', Rosemary Shrager would deserve it. Her cooking, balanced between modern professional and traditional bourgeois styles, is totally seductive. The technique reflects her mentor, Pierre Koffmann; her raw materials, from the Isle of Harris, have a unique sparkle; and the recipe development, clever but unfussy, is all her own.

Chefs' cookery books often justly stand charged with being impractical or, worse, with having recipes that don't work. They dilute what the Great Man does in his own kitchen into what his editor thinks the public can handle. But in Rosemary: Castle Cook there's never a sniff of compromise or dumbing down, yet the dishes are always accessible.

Fish and shellfish steal the show. Photographs of crab, lobster, "squatties" and langoustines bounce off the page. Simply prepared (roast lobster sauternes), naturally presented (scallops in a paper bag with egg noodle and ginger), sometimes with unexpected twists (herrings with couscous), they capture the spirit of the place just as Rick Stein's recipes do for Padstow.

The game dishes photograph less well, but their preparation is sensible, usually on the bone and accompanied with gutsy sauces. One, which goes with roast grouse, reads particularly well: celery, leek, shallot, red wine, stock, blackberry puree and rowan jelly.

There's no 'starter' section, and no 'vegetable' chapter either. Desserts are few and simple, though the homely Scottish baking at the end of the book contrasts quite dramatically with the tine cuisine preceding it. Ostensibly, the book ties in with the chef's Amhuinnsuidhe cookery school facing the island of Taransav. In fact, it's an object lesson in handling the finest produce.

If Rosemary Shrager is roaring with laughter on the cover of Rosemary, Castle Cook (and she is), you can understand why. She has what must be the almost unalloyed pleasure of running a summer cookery school in a castle overlooking the Sound of Taransay on the Isle of Harris, in the Scottish Hebrides.

Rosemary, Castle Cook is as much a tribute to this magically beautiful place as a record of her cooking. The cooking, in any case, is guided and coloured by the seasonal availability of the local ingredients. And what ingredients! Blessed with the best fish and shellfish in the world, feathered and furred game, fine beef and lamb, and soft fruit of unparalleled quality, Harris has much to offer the cook.

Rosemary Shrager's cooking is fairly straightforward, allowing the superb quality of her raw materials to emerge. She cooks pretty much in the French tradition (she has worked for Pierre Koffinann and Jean-Christophe Novelli), with results that are at once robust, elegant and subtle. Her Crab Risotto is flavoured with leek and shallot and garnished with mussels and peas. She pairs, sumptuously, turbot and lobster in a cream sauce. Seared medallions of venison sit on a bed of spinach surrounded by a deep fawn morel mushroom sauce.

The visual effect is as ravishing as the flavour must be superb. Puddings range from exquisite raspberry souffles to that crowning marvel of Scottish cookery, the Clootie Dumpling. If this book gives a true flavour of Rosemary Shrager's qualities as a teacher, then she must be inspiring indeed. The only pity is that we don't all have the same first-class produce on our doorsteps. That is hardly her fault, of course, so there is no reason to withhold an unreserved recommendation for the Castle Cook.