DURING this week 250 years ago – on May 16, 1763 to be precise – a meeting took place in a bookshop in London's Covent Garden that was to change the course of literature.

A young Ayrshire-man, James Boswell, brimming with charm, was introduced to the colossus of English letters, Samuel Johnson, compiler of the first great English dictionary. Despite Johnson's rough teasing of Boswell's Scottish-ness, their ensuing friendship lasted until Johnson's death, almost 22 years later, and led to Boswell's masterpiece, his Life of Johnson, which was published, with pleasing symmetry, on May 16, 1791.

Since then the title has never been out of print, and Boswell has long been recognised as the inventor of modern biography. "Ever since Boswell," states biographer of the moment, Charles Moore, "biography has been a dominant and popular form in the English language, particularly in Britain." And yet for all the plaudits, Boswell's light has dimmed compared to his equals, Burns, Scott and Stevenson. And this is why, three years ago, I launched the Boswell Book Festival, dedicated to biography and memoir, held at Boswell's family estate, Auchinleck, in Ayrshire.

In search of what made Boswell stand out as the inventor of modern biography, I turned to Dr Gordon Turnbull, who, as head of Yale University's Boswell Editions, the project bringing the vast collection of Boswell's private papers to publication, is uniquely qualified to set his achievement in context. "The great Dr. Johnson himself wrote that 'no species of writing seems more worthy of cultivation than biography'," says Dr Turnbull. "Fiction, poetry, drama, art and so on have immense cultural value, but biography has a special immediacy, a means of testing and measuring ourselves against other people's lives."

He continues: "Boswell came to this recognition early and intuitively, and the questions he asked are still the ones the festival's line-up of speakers on biography and memoir pursue in their own writing. He lived at the time that scholars later came to refer to as the Scottish Enlightenment. In the records of his own often-enough wayward life we find the great questions asked by, say, his teacher, Adam Smith – such as, what is the sympathy that holds human beings and communities together? – not in theoretical abstraction, but at street-level, lived out.

"That's the same sort of concern he brought to the biography of Johnson, and is why his meeting with Johnson 250 years ago was such a game-changer. What does a life-writer even now try to achieve but that very Boswellian sympathetic inhabitation of another's being, and present it to the wider world? And since the recovery of Boswell's private manuscripts, we now have his diaries, such as the London Journal 1762-1763, where we can see him seeking to work these urgent human questions out at autobiographical level."

As a former editor with the great Enlightenment publisher, John Murray, and living in Ayrshire, I could not understand how a writer of such genius could have fallen into neglect – especially as one of his earliest fans was Robert Burns. But whereas Burns has long had both a monument – itself the work of Boswell's son and heir, Sir Alexander, and his younger brother James – and a museum to honour his life and work, Boswell has had none. That is why The Boswell Trust was established in 2010 to restore the Boswell Mausoleum in Auchinleck churchyard and to create in the adjoining Boswell Aisle a centre to celebrate his life and work. However, something more dynamic was needed to bring Boswell's name back onto people's lips and to bring him alive today. Thus under the banner of the trust, the Boswell Book Festival was born.

Says Dr Turnbull, who will be among the speakers at the festival: "It couldn't be more fitting that Boswell and his family estate should give the festival's vibrant engagement with life-writing -- to quote Duke Theseus in A Midsummer Night's Dream – 'a local habitation and a name'."

For full details on the Boswell Book Festival, May17-19, visit www.boswellbookfestival.co.uk.

Caroline Knox is director of the Boswell Book Festival