The Devil's Playground by Nan Goldin

For a man who liked a good joke, Roland Barthes took a strangely glum view of photography. To photograph a thing, Barthes said, was to imply that it needed recording, which was to acknowledge its mortality. Preservation encompassed death. To shoot a thing was to kill it.

It's a thought that keeps coming back to you as you flick through The Devil's Playground, a new book of photographs by the Paris-based American artist, Nan Goldin. Partly, this is because death stalks the book in different guises like the characters in a medieval morality play. There's pestilence (in the form of heroin addiction, including the artist's own) and there's famine (the wracked bodies of addicts and Aids patients and anorexically thin women). Apart from these catastrophic causes of death, there's the ever-present one of age and decay - Goldin's octagenarian parents hugging on a couch or doing creaky t'ai chi in their bedroom - and a general connection, also strangely medieval, between nakedness and frailty: people called Guido and Clemens and Valérie and Cookie, naked, kissing, fucking, asleep in bed; bruised, hospitalised, dying, dead.

In all of this, though, there's a central death, or at least a central absence, and it's that of Goldin herself. Let's flick through The Devil's Playground again.

Here, at random, is a lovely shot dating from 1998: a kind of landscape-portrait, the shadow of a person on a bridge reflected on a Connecticut riverbed. Here's a Golden Age-ish still life of a breakfast tray - the caption tells us it's on a bed in a Florence hotel - and here, in a section called "From Here to Maternity", is the iconic portrait of a little Swedish girl in a romper suit, her hand raised in blessing like the Infant of Prague. Here, for want of a better term, is a history scene by Courbet: the hair of a dead woman, Sharon's mother, on a lace pillowcase at her wake, her daughter looking numbed. Here's Clemens, sitting in a chair in the room of a New York rehab hospital, looking hard at someone we can't see. And here's the someone in question, Goldin herself - Nan, in the demotic titling of this book - in mid-delirium while coming off heroin yet again at yet another hospital, this time in London in 2002.

So many people, so many places; so many artistic subsets and styles. Too many you might think, though you'd be wrong. The point about Goldin's work is that it's a journey between the first and last of the images above; which is to say, that it gets nowhere by way of just about everything.

The shadow in the first picture is Goldin's own, taken in the grounds of a hospital. The face in the last is also Goldin's, and taken in a hospital room. The self-portraits were made four years and a continent apart, although, in terms of their story, they might have been taken on the same day and roll of film. Which is their point, both the subjects of the pictures and the act of their making suggesting an addiction that never changes. Or two addictions. Goldin needs to shoot pictures, needs to shoot up. And it's this - the sense of dual compulsion, the urge to show other people's destruction by way of her own - that gives her work its genius.

The second of these two self-portraits sums it up. It's a picture of Goldin the heroin addict taken by Goldin the addicted photographer, and its inclusion is ruthless. One of the ghosts you sense in The Devil's Playground is of all the photographs that aren't there - the tens of thousands of images that must have been discarded to leave the 500-odd that remain. The pictures are as frail, as editable, as the people in them, the Aids patients, the shadows, the snowflakes, Nan Goldin. And you know that she's edited herself out, too, which may be as frightening as editing herself in. She is Barthes's photographic killer, but she is also his victim, murdering herself as she goes.

The curious thing about all this is that it suggests some kind of moral agenda in Goldin's work. Just as the excesses of medieval humanism meant that women could become saints by licking pus from lepers' wounds, so Goldin seems, at first glance, to be on a mission to beatify the damned, herself included. But that isn't quite as simple as it sounds.

The Devil's Playground was a term used by medieval Christians to denote an irreligious world outside their own, and Goldin seems mesmerised by religious iconography. Her mothers and babies are posed as madonnas and children, while the last section of her book, called "Relics", takes in ex voto medals, votive candles and statues of saints. But what is less clear is how we're meant to link these things up. Is the devil's playground the one we're looking at - a world where people shag to camera and show Goldin cut wrists and heroin eyes - or is it the one we're looking from? Are the photographs in The Devil's Playground a vision of addictive hell or of an addictive heaven - a world of trust and honesty known only to the wounded? Flick through the book as I may, I still can't decide.

In fact, I've changed my mind about this book about as often as I've flicked. At first it struck me as useless, in the literal sense of having no use. What do you do with a 500-odd-page tome that costs 60 quid and weighs half-a-stone hardbound? How can you read the story it has to tell? The book's world is one of failure and frailty, and yet using it calls for strong arms, deep pockets and an ordered life. It's a guide to suffering for people who don't suffer, which makes it seem vaguely distasteful.

Added to that, The Devil's Playground - published two long years after the Whitechapel show that gave it its name - has been a source of huge rowing between the artist and her publisher, and it shows. Bits of text, such as they are, are poor and opaque and sprinkled among the pictures any old how until they eventually peter out halfway through. And if you're of a neat mind, it's hard to tell exactly what kind of book The Devil's Playground is: not a catalogue, far less a catalogue raisonnée); not an artist's book, in the sense of a crafted artefact, nor yet an aren't-I-clever coffee-table book to be piled up with back copies of Frieze.

And yet, oddly, I find myself liking The Devil's Playground precisely for these faults. Where Goldin's Whitechapel show two years ago struck me as brash and over-blown, its hardback equivalent is movingly wonky. Images that passed me by when they were blown up and hung on a wall hit me here with a chill: in particular, one of a wreath on a grandmother's grave in Richmond-on-Thames, which Goldin spotted while coming off heroin, yet again, at The Priory. Spelt out in yellow geraniums, the wreath reads: NAN.