But Castledine’s progress has taken two forms. There’s the heavy-footed tread of lumpen productions like Uncle Vanya or last year’s Chichester Doll’s House. Then there’s the soaring flight of dream productions like Lady Audley’s Secret and the 1994 Contact Theatre Threepenny Opera.

Given her feminism, assertive but not aggressive, and her particular success with free-form, non-naturalistic theatre (in her hands Keatley’s My Mother Said I Never Should became a dream-woven symphony built round an onstage violinist), Castledine’s forthcoming production of Edith Wharton’s novel The House of Mirth - the final tour for Cambridge Theatre Company before its name change - should carry considerably better odds than a fistful of lottery tickets. And the prize could be as great - in spiritual if not cash terms. That’s a distinction important to Wharton’s picture of turn-of-the-century New York society where Wall Street profits lie behind Fifth Avenue gracious living.

House of Mirth has been a labour of love for Castledine and adapter Dawn Keeler for some years. Cambridge’s director Mike Alfreds heard of their project and scooped it for this tour. Adapted novels can be the dreariest type of theatre, but this will be no incident-by-incident slog through the action. “You express the novel theatrically by taking certain risks and liberties,” says Castledine. “That means you search for a theatrical form through which the novel, its themes, or its major concerns as you see them can be expressed. It has to be a very individual interpretation. We’ve constructed a scenario outside the scenario of the novel, through which to tell the story and express these major concerns.”

Accepting “everyone has difficulties with adaptations,” she is keeping her extra-Wharton scenario under wraps. Castledine sees her work over the years as a continuous process of experiment in which she sets herself creative challenges as an artist. Immediately she withdraws the word “artist”. Ever a commanding figure, Annie Castledine is never pompous. Her aim is to present the novel - minus, she accepts, much of Wharton’s sparkling description - with 10 actors and no doubling by focusing on the most important characters.

She believes Wharton’s concerns grew out of her experience. “It’s autobiographical. In theme if not narrative. A woman such as Edith Wharton, and therefore Lily Bart is a divided self.” By upbringing each “wants and is part of a society - the premier 400 of America at the time. And there’s a conflict with the inner values Edith and Lily possess, values of the interior life and spirit.” These are “absolutely at odds with society which is materialistic, inherently racist but showing duality of thinking (despising Sim the semite but fawning on Rosedale the rich) and preoccupied with all that wealth can buy.”

High society then in which there’s no such thing as society? Has a contemporary ring? Don’t worry. Annie Castledine is an artist, mining the novel for its truth not digging it over for cheap modern echoes. But she does break off mid-flow to say, surprisingly. “It’s pure melodrama.” What? “Melodrama is the most political of genres. It’s always about class, always shows the woman’s point of view.” High class melodrama, in all senses, to be sure. But Lily goes way beyond familiar melodramatic stereotypes. This will be recognised by her being the only character to communicate directly with the audience.

Communication being one of the major themes, maybe? Lily’s two natures are both alive from the start “but she does not care to communicate with her self. We see this early after the Bellomont bridge-party (it’s Book One, Chapter Three) when ‘Feeling no desire for the self-communion which awaited her in her room, she lingered on the broad stairway.’ When alone she always meets her other self. This frightens her, for it’s at odds with all she was brought up to believe and all those around her believe in.”

Lawrence Selden, who could help, is “deeply flawed. He could commit himself to feeling for Lily but doesn’t. He too easily believes the gossip of the society he despises but belongs to, so he fails to save Lily.” Ironically, better advice comes from a source she cannot accept, Sim Rosedale.

How much irony will pervade the staging is yet unclear. One scene that won’t be there is the visit to Nettie Struther’s home where the floating Lily glimpses how the poor woman, given a sense of purpose, has constructed a new life. It seems crucial to me, and Castledine is happy to enter into dialogue, indeed sees her productions as dialogue, with her audience. Her current Women of Troy for the National received a “bruising” critical thumbs-down but is playing to 80 per cent in the cavernous Olivier and finding a new, young audience. It’s due for a spot of re-rehearsal, partly in response to points in a letter from an audience member.

An epistolary night, for the same audience produced a letter from an A-level student saying how Castledine had made Greek tragedy live for her. With House of Mirth the director hopes her search for “a popular voice” will unite audiences. The novel’s scope, even - or especially - the way it uses surprisingly little dialogue, could provide Castledine with just the right material.

Tours until July 1 to Winchester, Warwick Arts Centre, Cheltenham, Darlington, Poole, Oxford, Canterbury, Buxton, Worthing. Details: 0171 401 9797.