Last Sunday dawned clear and cold. From my window, the valley was filled with the dry ice of drifting mist, like a boiling bath: small islands of trees poked spikily through, against a sky of forget-me-not blue, it dissolved wispily, while I listened to Alistair Cooke's Letter from America (R4), and I only mention the circumstances because of their pleasing aptness.

Cooke was describing just such an autumn morning, when he stood at his window in New York watching a single seagull fly in - looking, to his enraptured gaze, for all the world like a dove. It circled high over Central Park and was gone over the northern horizon, to tell its marvellous story. For all the world indeed, it was a jubilant day: overnight, mankind had been saved from the prospect of an imminent nuclear war.

There is nobody to touch Cooke at this kind of thing. He was there, in the presidential plane, when it wheeled round, returning Kennedy to Washington with the "cold" that heralded the Cuban Missile Crisis. Now, 35 years on, the documents are released and he is there again, recalling that tense and dangerous fortnight with the immediacy of the witness, the measured judgement of the historian and the skill of a first-rate story-teller. To the grateful listener, hazy memories of massing thunderclouds of war are replaced by clarity - and a huge sigh of retrospective relief.

Sorry, but there's no avoiding anniversaries this week. Five years before the Cuban incident, Today (R4) was born. For a while, on Tuesday morning, it seemed that the whole 40th-birthday programme was a joke. Was the government of Zaire really threatened by a Captain Solo? Is the boss of Summerhill, the defiantly liberal school, honestly called Zoe Red-Head? Do the French call little Noddy OuiOui? Can there be a Howard Gorgeous on the Hong Kong Stock Exchange?

Yes, more or less yes, yes and yes. The jocular element only came when jolly Ken Clarke was invited to dose John Humphrys with his own medicine in a knockabout interview, close to farce: there was a certain savage pleasure in hearing the biter bit. And the next morning they were back in their normal roles chewing over the EMU with Clarke still, clearly, feeling empowered to interrupt like a quiz-show buzzer.

Today attracts more than five million listeners a week, and depends heavily on its presenters. Possibly the best was Brian Redhead (no relation of the headmistress of Summerhill), who defined the programme as the place where people can drop a word in the ear of the nation. But the current bunch are doing pretty well. It is only when they become boringly enmeshed in hypothetical political argument that you want to hurl the radio across the room.

They have become used to reporting from wherever the big news happens, be it Lockerbie, Baghdad or Paris. And, because so many of us awaken to their voices, they have become indispensable. Who could forget, for example, the careful, appalled, sensitive reporting of James Naughtie from Dunblane? Tuesday's programme illustrated another of Today's great strengths: the informed foreign correspondent, in this case Jim Muir from Algeria. His account of the massacres there was thorough, and heartbreaking.

"Thought for the Day" attracts a lot of flak, but some of its presenters - like Lionel Blue - have become bywords for gentle humour. Bishop Bill Westwood was typical of the vague, benevolent episcopal maunderings that often feature when he struck a topical note on Tuesday, exhorting us all to live for Today. Jack de Manio - who, famously, couldn't tell the time - is long since departed, but even he did better than the hapless girl who announced, "it is 12 o'clock, Green Witch. Meantime, here is the news". Her unidentified voice featured in a good-humoured celebration of another anniversary, the 75th of the BBC itself. Denis Norden and Frank Muir (whose voice, though fruity as a Christmas pud, is beginning, sadly, to sound elderly) collaborated on Muir and Norden's Funny Old Auntie (R2), a miscellany that dug up many less famous moments. I particularly enjoyed Enid Trevor in the Forties, making an announcement as a V1 rocket-bomb fell on the Regent Palace Hotel. Heroically, she carried on - at twice the volume.

Sue Limb is also facing up to a birthday, her 50th. She can do no wrong for those of us who still yearn for a repeat of her glorious series The Wordsmiths of Gorsemere (please, Auntie: it wouldn't cost you much, would it?). Growing Pains (R4), while a little patchy, succeeds because of her heavenly irony. Springing from the gloomy realisation that she is suddenly older than the Prime Minister, it tackles the problem of the fiercer dark years of middle age. Her face and hands look like something venerated under glass in an Italian cathedral, she says, and the mirror shows her a woman who has poisoned four husbands - but she sounds magnificent. She should rejoice to have been born hereafter: On This Day (R4) reported that in 1947, the year of her birth, 500 factory workers went on strike because a woman was being bossy to them.

This seems as good a point as any to mention Music for the Bride (R3), a splendid account of the laments which accompany weddings in many cultures - yes laments, bewailing the loss of freedom, the endless household chores, etc, that marriage brings. Our dog was giving birth while I listened to the Breton threnody, played on bombard and bagpipe: it was tricky differentiating the sounds.

Now a big leap back to 1227, and the beginnings of Bedlam. The Bethlem and Maudsley Trust is heir to the hospital founded by monks of the Order of the Star of Bethlehem, an occasion that prompted All In The Mind (R4) to discuss the link between religion and psychiatry. In distress, should we turn to priest or shrink? Anthony Clare found a man who was both: he'd be the one for me.

OK, brace yourselves: back we go 1954 years to the arrival of the Emperor Claudius (also known as I Clavdivs) and the start of The Romans in Britain (R4) a resolutely up-beat series presented by a man with a name like a medieval chronicler and the relentless enthusiasm of a children's-party entertainer. Guy de la Bedoyere, accompanied by experts chosen for their strange voices (one seemed to be Donald Sinden, another a pizza-chef) exhorted us to burn our history books and discover the truth. Here's just one thing I learnt: en route to the conquest, Clavdivs asked a Frenchman what to call us. He said "Pritons", but Cloth-Ears Clavdivs misheard. Rule Pritannia.

Highlights from 'Today' are available on cassette from BBC Worldwide.