There's a fascinating discovery in the new exhibition of JD Salinger's letters in New York. A window into the world of the reclusive author of Catcher in the Rye, who died in January, it comprises just 10 letters and a postcard to his friend, the painter Michael Mitchell. In one, Salinger writes: "I have 10, 12 years' work piled around, but I don't know how soon it will be before I feel up to unloading any large part of it. I have two particular scripts - books, really - that I've been hoarding and picking at for years." There, finally, is confirmation that there is a tantalising archive of unpublished Salinger work.
These aren't the only letters of his to hit the headlines: Joyce Maynard auctioned her correspondence from 1972 with the author (the teenage Yale fresher moved in with the 53-year-old Salinger), much to his chagrin. Werner Kleeman, a comrade from the Second World War, has recently revealed that he too has a stash of letters that punctuated their long friendship. So will Salinger eventually be cast alongside Keats, Beckett, Chekhov and Van Gogh as one of the cultural world's great letter writers?
Admittedly, it's unlikely that Salinger's letter-writing legacy will match, say, Samuel Beckett's. Currently, there does not appear to be a huge archive to call on: the Morgan Library is having to show its first four now, and another six in April, to keep interest levels high. Still, the correspondence is causing a stir because, finally, we're gaining some insight into the intriguing world he kept from us. He would get up at 6am and write without interruption, "unless absolutely necessary or convenient".
In his letters, he seems to feel genuine remorse for his reclusive lifestyle, noting that he couldn't answer the telephone "without unconsciously gritting my teeth". Kleeman has said the letters he received were emotional and warm - not quite matching Salinger's image. Such interest in his letters has a subtext too: the act of letter-writing itself is fast becoming an anachronism as communication increasingly moves online. In future years, a lucky curator may acquire the contents of a hard drive and painstakingly print out e-mail exchanges, but it's impossible to think that this will be quite the same.
The slower, more thoughtful process of writing on paper means that letters do reveal more about their authors than we would otherwise know. John Keats, for example, will always be one of the great Romantic poets, but he was also an insatiable letter-writer - his missives to his brother George in America became an internal, questioning diary that continually asked what being a poet actually meant.
He was not quite as insatiable as Beckett, though. The playwright scribbled a staggering 15,000 letters in his lifetime, equivalent to writing one a day for 41 years. The Letters of Samuel Beckett: Volume One was published last year, taking in the young writer's life in Paris, his rejections by publishers, his battles with rowdy neighbours and the death of his father. Anton Chekhov was another prolific letter-writer, the Russian dramatist's correspondence - often containing advice to his contemporaries - a road map for 20th- and 21st-century theatre.
The principle of Chekhov's Gun - where a seemingly unimportant element or object is introduced to a story and eventually proves vital to the plot - has become one of the defining tenets of modern writing. It was first mentioned to Aleksandr Lazarev in an 1889 Chekhov letter. It is difficult to point to many modern equivalents of Beckett, Keats or Chekhov. Perhaps that's why there appears to be a new preoccupation with famous letter-writers. The blockbuster exhibition currently running at the Royal Academy in London is The Real van Gogh: The Artist and His Letters.
It comes hard on the heels of a glorious (and expensive) book, Vincent van Gogh: The Letters, in which all of the post-Impressionist painter's correspondence (and there are 819 letters, 658 to his brother Theo) are published. They reveal a man contorted by the pressures of genius and ambition, but also more day to day worries over his finances and artistic reputation. All are available to browse through at www.vangogh letters.org, and they confirm his painterly vision - some letters are clearly literary blueprints for work he would later complete with a paintbrush rather than a pen.
So if, in 100 years time, we're still holding up Salinger's letters as proof of his genius, his internal battles and his well-hidden humanity, then he will truly have gone down in history as a great letter writer. That is if, of course, anyone still understands the concept of a finely crafted letter in 2110...