"Arriving Padstow 5.30 stop Tall and divinely handsome in grey." Even the tight constraints of a telegram couldn't strangle Coward's personality - here leading his unamused hosts to "keep a close eye on their fourteen-year-old son". Brevity, however, is not the point of Barry Day's eccentrically compiled selection, every bit as chatty and larded with the word "darlingest" as could be hoped. Letters from Coward's correspondents - his mother and secretary nestling alongside Virginia Woolf, Edith Sitwell and Marlene Dietrich - leave the reader feeling like an observer at an endlessly witty, if somewhat tiring, dinner party, although the most compelling chapter comprises solid exchanges with such unlikely literary allies as Harold Pinter and Arnold Wesker. By Coward's final "Good night, my darlings", it's impossible not to agree with the telegram he sent his mother on his 50th birthday: "Fifty years ago today / Teddington was decked and flowered / even God was heard to say / well done Violet Agnes Coward."

Noël Coward would, I'm sure, be horrified by many of the modern forms of communication. I can't imagine him being fluent in textspeak, for instance (Noël Coward, author of The 4tex and Hay Feva, doesn't look quite right). The immediacy of email would dilute such carefully thought-out witticisms as: 'I like long walks, especially when they are taken by people who annoy me.' On Facebook, however, he would be in his element, accepting 'friend' requests at the rate of several hundred a day.

One of the most striking things about Barry Day's sensitively edited collection of Coward's letters is the realisation that the playwright made friends like other people make noise. He kept up these friendships over decades, shooting off epigrammatic letters with astonishing regularity, sometimes even writing to people he disliked in order to charm them into submission (Graham Greene, an early critic of Coward's plays, was sent a retaliatory letter in verse: 'I know a few/ Politer critics than yourself/ Who simply hate my lighter plays/ But do they state their sharp dispraise/ With such surprising, rising bile?/ Oh dear me no, they merely smile.')

His correspondents included Laurence Olivier, Virginia Woolf, Ian Fleming, TE Lawrence and Lord Mountbatten and his letters gloss delightfully over some of the most important events of the 20th century. During the Second World War, he was recruited by spymaster Bill Stephenson: 'My disguise would be my own reputation as a bit of an idiot.'

The correspondence drips with panache, but is occasionally stifled by Coward's penchant for deliberately not taking things seriously. There are more 'Darlingests' here than you can shake an orchestral baton at. When news of the Profumo affair broke, Coward wrote to Jack Profumo's wife, actress Valerie Hobson: 'I said that although I didn't know the ins and outs of the situation etc', and then added in brackets: 'Perhaps this could have been more happily put!'

Yet for all this, Coward's letters remain peepholes into a gilded age. Each page is full of comedic vignettes that sparkle with shards of his lethal perception. And on top of that, he also makes you giggle.