Alan Davidson, who has died aged 79, was an engaging polymath in all matters of food. A writer of distinction, he was not just interested in cookery, but also its lore, ethnography and history, as well as the taxonomy of edible species.
He used his postings as a diplomat with the Foreign Office as an opportunity to unearth the culinary secrets of the places he visited, resulting in many place-specific books - often centred on his passion for fish - from his Mediterranean Seafood (1972) to Seafood Of South East Asia (1979).
The son of a tax inspector and proud of his Scottish forebears, he was born in Northern Ireland and educated at Leeds grammar school and Queen's College, Oxford, where he took a double first in classics. His time at university was interrupted by military service in the Royal Naval Volunteer Reserve from 1943 to 1946, first as an ordinary seaman, later a lieutenant, in the Pacific, the North Atlantic and the Mediterranean. He somewhat shamefacedly recalled slicing a whale in two when officer of the watch aboard the aircraft carrier Formidable. Perhaps his books were a penance for this accident.
A man of his qualifications was a perfect match for the Foreign Office, which he joined in 1948. His career took in Washington (1950-53), The Hague (1953-55), Cairo (1959-61), Tunis (1962-64), Brussels (where he was head of chancery of the British delegation to Nato, 1968-71) and, finally, Laos, where he was ambassador (1973-75). These postings were interspersed with stints as a "Whitehall warrior" on various desks at the Foreign Office in London. During his time in Washington, he met and married Jane Macatee, the daughter of an American diplomat. Having a foreign wife (even from a friendly power) set a British diplomat apart - Davidson was ever distinctive.
He decided to retire from the Foreign Office long before his time was up. He put that down to strong pressure from his wife and three daughters - to whom he was touchingly devoted and with whom he maintained a lifelong dialogue on rights and wrongs, little or big. They feared "he would become insufferably pompous if he had another ambassadorial post". He also ascribed the move to irritation with life behind a desk when confined to Whitehall; and to the siren call of a new vocation, to be a writer.
Not long ashore in 1946, he had sent a piece to Punch (its humour deprecatory) and, while at Oxford, had written several articles for Oxford Viewpoint - one of which earned him the comment "delightful" from Evelyn Waugh. His opportunity did not arrive until he was head of chancery in Tunis in 1961. His wife was understandably muddled by the various names proffered for one sort of fish or another in the local markets, and he promised to compile a list. He was fortunate in the arrival of the Italian professor Giorgio Bini, the world's greatest living authority on seafish in the Mediterranean, as part of an official delegation to discuss the dynamiting of their catch by Sicilian fishermen in the Gulf of Tunis. As the negotiations were long and largely political, Bini (no politician) was able to instruct the Briton in elementary ichthyology. Out of these lessons, Seafish Of Tunisia And The Central Mediterranean was born. Published by Davidson himself in 1963, it was followed the next year by Snakes And Scorpions Found In The Land Of Tunisia. At that stage, his passion seemed to be for taxonomy, not fish dinners.
A colleague, who had known the food writer Elizabeth David when she was working in wartime Cairo, sent her a copy of the fish book, and she reviewed it in her column for the Spectator. From this first contact flowed the process of its conversion from pamphlet to the full-blown work Mediterranean Seafood, published by Penguin in 1972. Elizabeth David, ever watchful of professional values, had advised the diplomat to avoid self-publication and had recommended him to her editor at Penguin, Jill Norman. These relationships were to be fruitful, both for later books on fish and food, and in the genesis of Davidson's publishing house Prospect Books in 1979 and its journal of food studies Petits Propos Culinaires, edited and published by Davidson until 2000.
Once he had embarked on a career as a writer, diplomacy did not lose him, but books kept appearing. While part of the British delegation to Nato in Brussels - a posting mired in international protocol - he buoyed the spirits by composing a thriller of quixotic inventiveness called Something Quite Big. It revolved around the mass kidnap of the alliance's heads of mission by wholly admirable eco-terrorists led by a most gorgeous and purposive heroine (he was always impressed by beautiful women). Its climax saw the diplomats released, wending their way to safety on bicycles (the book contained much incidental lore on the history of cycling - Belgium's gift to humanity was the bicycle chain).
This happy book did not occasion smiles in Whitehall. Permission to publish was refused for the sake of preserving official secrets: more likely for his sense of the ridiculous. He purged his frustration with the less alluring The Role Of TheUncommitted European Countries In East-West Relations, which was the outcome of a visiting fellowship at Sussex University in 1971-72, before he was posted to Laos the following year.
As he navigated the streets of the elegant capital, Vientiane, in his stately Bentley, the new ambassador was witness to the final days of the uneasy coalition between the royal dynasty and the Pathet Lao communist insurgents. When Vietnam and Cambodia fell to the communists, so they assumed control of Laos. A diaspora ensued, and the illustrations in many of Davidson's books by the Lao artist Soun Vannithone - now based in London - are one happy consequence.
With Mediterranean Seafood now published, he deemed a literal reading of the Foreign Office's prohibition of Something Quite Big to allow private circulation - so had it printed, with many errors, by a Catholic priest in the back streets of Bangkok. Curiosity about Laos and its culture resulted in his unearthing a cookery text used in royal circles. This was to become Traditional Recipes Of Laos (1981). His investigations into fish in the Mekong and other inland waters were published as Fish And Fish Dishes Of Laos (1975). His interests made the politics more pleasing. An especially turgid, yet delicate, negotiation with the Pathet Lao was transformed by his queries about snakehead fish that swim in the rice paddies, unstopping a happy vein of reminiscence from the opposition leader.
His sojourn in Laos produced one more book, Seafood Of South East Asia. It was also the finish of his official duties, with the graceful golden handshake of a short fellowship at St Antony's College, Oxford.
The first years of retirement saw a flurry of work, from a translation and abridgement (in partnership with his wife) of Alexandre Dumas' encyclopedia of food - Dumas On Food (1978), to the publication of his North Atlantic Seafood (1979), to putting in place, in 1978, a deal with Oxford University Press to commence his magnum opus, The Oxford Companion To Food, not to see the light until 1999.
He was working at a time when there was a growing eagerness for writing about food and cookery that went beyond the simple recipes for weekend magazines. There was a hunger for fine writing and additions to knowledge that did not indulge the bibulous fatuities of gourmets and gastronomes. He never could abide Brillat-Savarin and the panoply of theory around simple issues of hunger and pleasure erected by the French in the 19th century, and blenched at pretension. His mindset was questing pragmatism, leavened by surreal, puckish humour. His dislike of snobbery underlay his wish to return his CMG (awarded in 1975, but unrecorded in his Who's Who entry).
People of a like mind purchased the reprinted classics of the kitchen shelf that he began to issue under the imprint of Prospect Books from 1982 onwards, as well as the original titles about Tibetan, Indonesian or Majorcan food, and a wider public still was to applaud his handsome edition of Patience Gray's timeless contemplation of Mediterranean life and its relation to food and cookery, Honey From A Weed, first published in 1986. Prospect Books and its associated journal (where you could discover anything from the history of ice-cream to the niceties of Thai funeral cookbooks) were to swallow much time, too much indeed for speedy completion of the Companion. So, too, were the annual gatherings of food enthusiasts (he was careful always to call them "semi-academic"; he disliked arid scholarship almost as much as gastronomy) at St Antony's College that he organised with the historian of 19th and 20th-century France, Theodore Zeldin. It was a conference with a character all its own, slightly chaotic, a colourful group of egoists happy, for once, to listen to others, though often happier to criticise.
These activities on behalf of others made Alan and Jane's house in Chelsea an international caravanserai of scholar-cooks, many contributing his or her tithe of knowledge to the slowly accumulating Companion. Progress never had a disciplined air until his indefatigable assistant Helen Saberi imposed calm order. It was also held up by a serious heart attack in the early 1990s - this contributed to his dropping Prospect Books, which I took over in 1993 (my first title was his Something Quite Big, with fewer misprints).
The Companion appeared at the end of the millennium to just acclaim, and gained every prize going for food writing. More than a million words, mostly his own, displayed wit, humanity, curiosity and knowledge in equal measure. He eschewed the anthropology or sociology of cookery, and indeed the Byzantine ramifications of haute cuisine, for a delight in describing the most arcane ingredients or the complex lineage of food customs, recipes and techniques.
When the Companion was completed, there were many signs that he had had enough of food writing and wished only to turn to his new preoccupation: Hollywood filmstars of the 1930s and 1940s. My daughter spent many hours helping install the best video software to record film clips; and earlier this year she guided him through the streets of Los Angeles in search of film libraries. The lure of the movies did not stop him, however, from issuing one last book, on trifle (with Helen Saberi) and from supervising the republication of his three great seafood books, both here and in the United States.
Alan will be remembered for his charm, which was rarely used knowingly; his innocence, which engendered a constant public optimism; his stubborn itch for accuracy, perhaps encouraged by diplomatic training; and his handsome daily turnout in gay but never garish clothing (an affection for silks and American checks), complete with impressive shopping bag, or even three.
He is survived by his wife and daughters.
· Alan Eaton Davidson, diplomat and food writer, born March 30 1924; died December 2 2003