This love story begins with two gerontic delinquents driving along the northern bypass of Oxford and enjoying the ‘hoots and shouts from passing cars who have had to brake at speed’. At this point, the oldies judder off on to the grassy verge, leave the car, worm their way through a gap in the hedge and slither down to the River Windrush, where they strip off and bathe. No hint is given in these opening paragraphs of the woman’s state of mind. Instead, the bathe takes the narrator back in time to the first occasion when they had gone to that spot, forty years and more ago. Naked then (now they wear clothes – she an antiquated bathing dress in which he has had to dress her, he a vest), they had crawled out and dried themselves on Iris’s waist-slip.

I still have the waist-slip, I recliscovered it the other day, bunched up at the back of the drawer, stiff with powdery traces of dry mud …. Could someone, later my wife, have indeed worn such a garment?

After the initial bathe, the one in the 1950s, Iris had taken him to luncheon with a male admirer who evidently hoped she would be alone, and that she would spend the afternoon with him in his borrowed flat. And this is the point at which the reader is introduced to the story of how John Bayley, then a fledgeling don, came to woo and to win a philosopher from St Anne’s College called Iris Murdoch.

The newspapers have bid prodigious sums for extracts from this memoir, and it will no doubt be sold as an example of the modern confessional literature. We love nothing more, it would seem, than to read about illness. Various journalists have made names for themselves writing about cancer. Iris Murdoch suffers from Alzheimer’s disease. It is hard, though, to think of many caring husbands in positions similar to John Bayley’s ‘identifying’ with this extremely eccentric couple, who have made a point of never doing any housework, or employing domestics, in nearly forty-five years together; who have never had children; and whose distinctive relationship, obviously far more harmonious than most marriages one knows, has been a talking point since the Fifties.

Two of their closest friends have described to me having John and Iris to stay shortly after they were married. The man had been at school with Bayley, and his wife had come to know and like him, while being a shade wary of ‘intellectuals’ and dons. She was even more alarmed when she heard that John had married a philosopher, an expert on Jean-Paul Sartre, etc. Would the Bayleys be heavy going? After their first night, my friend decided to take them in a cup of early morning tea. She opened their bedroom door and was greeted with the sight of Iris, sitting bolt upright against the pillows, studying a German grammar. John, in a vest, was lolling relaxedly beside her, deeply engrossed in a copy of Woman’s Realm. There are thousands of stories about the Bayleys, which circulate among their hundreds of friends and acquaintances. They are unique in Oxford: in thirty years, I have never heard anyone say anything hostile about either of them. Quite an achievement in a snake-pit.

The wider public who are addicts of Iris’s novels will be struck by the disparity between the cool serenity of her philosophical writings and the tormented chaos of the lives she depicts in her fiction. Whereas the non-fiction proclaims the Sovereignty of the Good, the novels seem so often (although they contain ‘good’ characters) to suggest the Sovereignty of the Bad. The early books in particular, the first ten or so, are filled with emotional chaotics, misguided seekers, unscrupulous gurus or Dichter.

John Bayley’s story provides the clue which explains this noticeable disparity. It is not primarily a study of Alzheimer’s disease – although the passages in which Old Iris is described are wonderfully vivid and affectionate. It is, rather, the story of how, with tremendous subtlety and tenacious love, he saw off Young Iris’s other suitors. He changes, or omits, many of the names. It will be for a later biographer to supply them. The portrait of Elias Canetti, for example, is satisfyingly deadly. At the end, the weasels and stoats have been seen off and Toad Hall is repossessed; Ithaca is regained and the suitors are gone. It was only in the good-humoured and calm (if prodigiously messy) domestic shell provided by Bayley that Iris’s wild earlier selves could find a happy resting place and turn themselves into fiction. He is ‘the onlie begetter’, ‘il miglior fabbro’. He is far too clever, stylish and modest to make this claim for himself, of course: but it is this simple fact which these too short pages proclaim. And that is why this book is not merely autobiography. It is a continuation of Bayley’s great work as a critic.