A new biography of Agatha Christie claims, finally, to have solved the mystery of what happened during those 11 days in 1926 when the reigning "queen of crime" went missing, and was presumed by many to be dead. Christie turned up, of course, at a rather nice hotel 300 miles away in Harrogate. Andrew Norman, the author of Agatha Christie, The Finished Portrait, suggests that Christie was in the grip of a mental condition known as a "fugue state" or a period of out-of-body amnesia induced by stress.

Whether or not Norman's theory stands up - he is a doctor, which always adds a touch of legitimacy to these kinds of speculations - the interesting thing is the way that the story of Agatha Christie's lost fortnight 80 years ago still runs and runs. Just as Christie produced scores of novels that dealt with the disruption of the everyday by unknown (until the last page) forces, written for a predominately female audience, so she helpfully replicated this plot in her own life. Christie's existence, aside from the fact that she was a best-selling author, was like that of any other middle-class wife and mother with a nice house in Berkshire and her own Morris Cowley to run around in. But those 11 days when that identity was in suspension and a new one took over (she was found living in Harrogate under the name Teresa Neale) roused the whole country to a frenzy of speculation and anticipation. Even the home secretary was personally involved in the hunt for the missing woman.

Women - as both readers and writers - have always been intensely drawn to narratives in which, at the centre, there is a dark hole, a rent in the fabric of the everyday. In the 1860s this took the form of what was known as "sensation fiction" in which writers such as Mrs Henry Wood (like Christie she went by her married name) created stories in which heroines vanished, only to pop up in another guise entirely. In Wood's East Lynne, for instance, Lady Isabel Vane leaves her marital home for an ill-advised spot of adultery, gets horribly disfigured in a railway accident, and reappears, heavily veiled, to work as a governess to her own much-missed children.

Literary historians will tell you that it is no coincidence that sensation fiction started to make its appearance just as middle-class women began to agitate for better education, employment and legal rights. This desire to puncture the patriarchal fabric of society was mirrored in contemporary novels by plotlines in which the normal ways of carrying on were brutally disrupted. Heroines disappear, get locked up or, in extreme cases, are carried off overseas to start new lives in the sultan's harem. For whole chapters at a time they are living lives which require them to be resourceful, brave and, just sometimes, sexually indiscreet. And then, in the final pages of the book, the mystery is solved (Vane reveals her true identity to her children), identities and fortunes are returned to their rightful owners, and the order of the everyday continues.

Whether or not Agatha Christie was conscious of what she was doing during those 11 fugitive days - Andrew Norman says not - she was enacting a narrative that has appealed to women for as long as anyone started making up stories. Apparently Christie's life was not going well. Despite the fact that her latest book was selling wonderfully, her husband was deeply embroiled with another woman. The fact that she ended up in a spa hotel in Harrogate will speak to any woman deep in the demands of half-term who dreams about spending even a half-day being looked after by people who are paid to knead her clenched shoulders and paint her toes a pretty shade of pink.

The way she booked in under another name will appeal to anyone who has imagined, wistfully, what her life might be like if she started again as someone else. And the fact, finally, that Christie snapped out of her "fugue state" and allowed herself to be restored to her true identity will make a sad kind of sense to all of us who know that, while we may occasionally take a holiday from our everyday lives, at some point we will be obliged to return.