Jane Austen's novels pose a challenge for criticism. Something in the texture of her writing – its conversational ease, high spirits, bourgeois-domestic subject matter – confounds the heavy machinery of the academic critical apparatus. (Confounds it, but needless to say doesn't deter it.) Isn't it possible to do justice to the importance of the novels without trampling all over the reader's fresh pleasures and burying the point of the reading along with its innocence? On the other hand, a respectable critic doesn't want to end up sounding like the "Janeites" who warble so wonderfully through Claudia Johnson's history of Austen cults, gushing about her "indefinable charm" and "bright sunny nature", and her life that "passed calmly and smoothly, resembling some translucent stream which meanders through our English meadows".

Here are two readable, gossipy, involving books about Austen that more or less manage to square this critical circle (and any reader of Austen knows that gossip is no inferior indulgence, but the essence of narrative). Both critics refrain from offering new interpretations of the novels. Mullan's What Matters in Jane Austen is a kind of concordance of their contents, broken up into chapters with headings such as "Do We Ever See the Lower Classes?" and "How Much Money Is Enough?" (The book is excellent on money, and on how everyone knows how much everyone else is worth.) Johnson's book, Jane Austen's Cults and Cultures (University of Chicago Press, £22.50) is an exercise in literary sociology, trying to pin down the meaning of a national and international obsession. Why does a cult attach precisely to the least cultish, most pragmatic of English writers?

Austen published anonymously (as "A Lady"); in her own lifetime she had no public life as a writer among writers. She had a generous critic-champion in Walter Scott, but if her work was read at all (and after her death she was out of print for 12 years) it was thought of as being on the genteel, female margins of literary culture. It's a teasing conundrum that she could not possibly – could she? – have imagined the scale and the kind of the appreciation that was to follow. ("Did Jane Austen know how good she was?" Mullan asks at the opening of his book; a conundrum even more difficult to unpick.) By the end of the 19th century enthusiasts were making pilgrimages to "Austen-land", imagining themselves communing with her "mind and heart", fancying "girlish forms … walking among trees and flowers at Steventon". Like other pilgrims, Johnson is haunted in pursuit of Jane, disappointed because the cottage at Chawton is "charmless … a functional edifice, not a cosy one", and by the labels on the furniture: "Although this piano is not the one Jane Austen used, she bought a similar type", and so on.

Johnson identifies different elements in the enthusiasm. The late Victorians, tired of sensationalism, wrote about her "magic", and needed her to reinvest "the world with wonder". She was carried to the remote corners of empire as a talisman of English values; hardened soldiers in both world wars hung on to her disabused clear-sightedness. Kipling writes a short story about the Janeites, mystifying them as a sort of Masonic sub-cult. But what is it about these novels that makes them into the repository for so much longing? Partly, it may be the seeming plainness of her prose, which means it's easy for all sorts of readers to pour themselves into her sentences and her worlds, identify with her way of seeing. The intelligentsia can't keep her to themselves; in fact, the power of Austen's writing seems disproportionate to the purchase it offers for interpretation. A book like Mullan's, put together about Henry James, say, would seem too unsophisticated and vaguely insulting ("Is It Polite for a Man to Sit Down When a Woman's Talking?" or "How Easy Was It to Get Divorced?"); too much of what James is doing, at any given moment of his prose, can't be resolved to solidities. How can an art almost entirely composed of the items Mullan enumerates in his book (the cost of keeping a carriage, the sleeping arrangements for sisters, the weather, card games) add up to greatness?

One effect of reading Mullen's compendium is to make you appreciate the sheer density, the tight-woven intricacy, of every scene and every exchange in Austen. His approach illuminates, because no detail is redundant: Mrs Norris scolding the carpenter's son, or Mr Perry's children eating wedding cake, or Captain Benwick's taste in literature. Every remark, every accident, every material exchange, is a revelation. Rather, each detail reveals just itself, its own place in the whole unfolding story of how things are, at a specific place and moment in time, in a specific nexus of human relations – in Highbury, or at the Camden Place evening party, or between Mary Musgrove and her in-laws. "How things are" is obvious, once you can see it; it's easy to read, once it's written. What's less easy is to imagine holding all that material at once in imagination, and finding the right run of words to put it on to the page; making sentences unroll convincingly into an illusion of seeing and hearing, movement and intelligence. If it works, then reading is like a sensation of being there. Janeites obsess over belonging inside her worlds, because she makes us all feel present in them; she includes us in the club of those who see.

Here's a little scene in Mansfield Park, which Mullan rightly makes much of:

"I think the man who could often quarrel with Fanny," said Edmund, affectionately, "must be beyond the reach of any sermons."

Fanny turned further into the window; and Miss Crawford had only time to say, in a pleasant manner, "I fancy Miss Price has been more used to deserve praise than to hear it," when being earnestly invited by the Miss Bertrams to join in a glee, she tripped off to the instrument, leaving Edmund looking after her in an ecstasy of admiration of all her many virtues, from her obliging manners down to her light and graceful tread.

We're feeling from Fanny's point of view, but we're also seeing Fanny, from Edmund's and from Mary's – and they're watching each other. Her speechless turning away "dramatises the pitch of Fanny's feeling", as Mullan says. The other two seem to be falling for each other (redoubling her pain) almost through Fanny's mediating sweetness, which brings out their best selves; we experience from moment to moment the excitement running around through the heated and averted gazes. (It's a shame that "Is There Any Sex in Jane Austen?" restricts itself to examples of adultery and illegitimacy, and the problem of male appetites, rather than trying to catch the sexiness on the page.)

Austen's achievement depended on her penetrating intelligence, which saw so clearly; and on her strong instinct for the rhythms of story form. But her genius was in being able to imagine, better than anybody else anywhere had done up to that point, just how much the novel narrative could do in constituting this illusion of presence. Mullan includes extracts from Austen's contemporaries Fanny Burney and Maria Edgeworth to make the point that although they're very good, the difference is vast. And Austen's work is everywhere so fresh, just because she's at the beginning of this new realism, before it's worn into its cultural groove. Some of the features that Mullan analyses as stylistic strategies – surprise switches of perspective, sudden unexpected authorial interventions, repetitions of the same word over and over – may well be strategies, but they're also aspects of her lucky freedom, making up the conventions as she goes along, answerable to no one's expectations. (Mullan's trawling of individual words throws up, for example, an inordinate amount of "blushing", used almost as shorthand for responsiveness. And there are 15 "blunders" in Emma: nobody's editor would allow that now.)

Mullan draws his examples from all six published novels, and doesn't have room inside his book for the discrimination that they aren't all equally good, judged by the standards of Austen's own best work: though they are all six very funny. Northanger Abbey is too slight, too dependent on one joke (and Catherine isn't interesting enough to carry the narrative's intelligence). Sense and Sensibility is deeper, and fascinating, but too wooden (though there's a wonderfully rich scene near the end, where Elinor is watching over Marianne's illness, waiting for their mother to arrive). There are creaky and thin bits even in Pride and Prejudice: the two aspects of Darcy's character (haughty and prejudiced, with dignified and sensitive) seem yoked together unconvincingly, for the sake of his delicious about-turn. Austen is feeling her way, across these first three novels, into a brand new kind of fiction.

• Tessa Hadley's latest book is Married Love (Jonathan Cape).