Claire Harman’s career has been defined by digging. As a literary biographer, who has written about Robert Louis Stevenson, Fanny Burney, Sylvia Townsend Warner and, most recently, Jane Austen, she is an expert excavator. She delves into the lives of famous writers, rooting around for biographical detail to enrich our understanding.

“I like literary biography because you can see the shapes in writers’ lives in more complex ways,” she says. “On the one hand, Robert Louis Stevenson wrote to make money – he had an extended family to support, with several children belonging to his wife from a previous marriage – but he was also writing on themes that had obsessed him for decades. His books were culminations, in a way, as well as being slightly throwaway potboilers.”

Claire has lived in Oxford for 16 years. She used to teach English literature at St Catherine’s College, but now labels herself a freelance writer (in fact, she still teaches creative writing part-time at Columbia University in New York).

Her most recent book, Jane’s Fame, dissecting the history of Jane Austen’s popularity, was published earlier this year; she has also written introductions to new editions of Kidnapped by Robert Louis Stevenson and Summer Will Show by Sylvia Townsend Warner.

Only, there’s a problem: how many people actually read literary classics? Harman makes an interesting point.

Writers like Stevenson and Austen have been responsible for some of the most famous works in British fiction (admittedly, early 20th-century poet and novelist Sylvia Townsend Thompson is less of a celebrity, though Harman describes her as a “great stylist...very wry and witty in an off-the-wall way”). But one of the great ironies about such classic works, says Harman, is that they can become casualties of their own success. Not many people actually read really famous works because they know the story already from our culture,” she says. “In a weird sort of way, these books get rather neglected when they are massively famous. They become invisible.”

Jane Austen’s novels certainly fall into this category. I, for one, hold my hand up to watching Ang Lee’s film version of Sense and Sensibility and the BBC’s 1990s Pride and Prejudice, then deciding that I’d probably done both novels. The renown of Austen’s sensual and yet sharply incisive romantic dramas extends far beyond her actual readership and it is this aspect of the widely loved early 19th-century author that Harman explores in her most recent book, Jane’s Fame: How Jane Austen Conquered the World. As with many literary luminaries, Austen’s fame in her lifetime was fairly limited. She was regarded as a ‘niche taste’ at the time of initial publication, says Harman, and she only attained mass appeal several decades after her death, in the late 19th century, when a biography of her emerged, followed by highly popular illustrated versions of her stories.

Of course, 100 years later a second wave of Austenophilia descended when BBC commissioning editors and Hollywood filmmakers took a fresh interest in her novels. So what is it about Austen that has secured her ongoing popularity almost 200 years after her death? First, her stories work on two distinct levels, says Harman.

Schoolchildren can read them and enjoy them as the period romances they purport to be – they are clearly written and very comprehensible – but then, when you return to them as an adult, you suddenly detect the irony that pervades her narratives.

“The worldliness of the novels goes over the heads of most teenagers. When you come back to the novels as an adult you can see the cynicism underneath the stories.”

Robert Louis Stevenson enjoyed more fame and wealth during his lifetime, but then he consciously sought to write books that would sell. Treasure Island made him an instant star (it was serialised at first, then turned into a book): “He basked in the afterglow of those books for the rest of his life.”

Jane’s Fame: How Jane Austen Conquered the World, Canongate, £20.