The publication of a book called White, by the cultural critic Richard Dyer, would seem, at first glance, to fill an obvious gap in the market. Wander into the media studies section of any large bookshop and you can find vexed and anxious works about the representation of women, blacks, gays and disabled people. Indeed, wander through the right bookshop and it can feel as if very little else is being studied in universities but the myriad forms of disadvantage and oppression that the modern world throws up. You're nothing if you're not a victim these days and the absence of "white studies" from this roster is telling, as Dyer points out in his introduction - in his view it's a mark not of exclusion but of an inclusion so complete and unquestioned that it doesn't even have a name: what would white issues be about exactly?

If you can't quite judge his book by its cover, the jacket does, at least, offer an elegant encapsulation of what it encloses: a blank page from which the word "white" has been punched out, allowing you to glimpse the luscious flesh tones of a Bouguereau print behind it. Two of Dyer's themes are neatly alluded to by this design; first, that the use of "white" as a description of skin colour needs some kind of explanation, and secondly that ideas of whiteness are a sort of void which shapes the way we look at the world. It isn't mentioned because it is taken for granted, he says, and the silence is ominous: "This assumption that white people are just people, which is not far off saying that whites are people whereas other colours are something else, is endemic to white culture". I would argue that it is endemic to any dominant culture, whether that is Inuit or English - but I'm less interested here in taking on Dyer's detailed arguments than in examining the academic culture which they themselves reflect, the chief feature of which is a presumption of Western guilt.

Dyer's introduction is a masterpiece of anxiety and it vividly conveys to a non-academic reader the sort of vertigo induced by a raised consciousness. Your eyes are opened, and you find yourself teetering on a tiny ledge above the abyss of Unreflecting Prejudice. Only the utmost care will prevent you from falling; one slip of the tongue and your standing is gone. (And if the geography sounds a bit like Bunyan, then that is hardly surprising because this is essentially the latest flowering of a long intellectual tradition in British thought - that of Nonconformist self- flagellation.)

Dyer, for instance, begins with a kind of confession of error - an account of his own sexual tastes and relevant humiliations which serves as a pre- emptive declaration of unworthiness. He recalls a moment when he found himself dancing between lines of black people, dismayed and alienated that his own sense of rhythm did not match theirs. "It brought home to me that, in my very limbs, I had not the kinship with black people that I wanted to have." (It is slightly surprising, given that Dyer is Professor of Film Studies at Warwick University, that he doesn't mention here a canonical moment in The Jerk, in which Steve Martin, who has been brought up by black sharecroppers and has been baffled by his clumsiness during family hoedowns, inadvertently tunes in to a white easy-listening station and finds his fingers snapping in perfect time. Then again, levity is not a big element in this type of work.)

Dyer is not bigoted about whites, you understand - "Goodwill is not unheard of in white people's engagement with others," he notes at one point - but he is keenly aware of their shortcomings. Indeed this raises anxieties about the whole enterprise: "Writing about whiteness gives white people the go-ahead to write and talk about what in any case we have always talked about: ourselves". There is some consolation in feeling bad about this but... beware that ye fall not into perverse pride: "We may lacerate ourselves with admission of our guilt," he writes, "but that bears witness to the fineness of a moral spirit that can feel such guilt". Every thought only adds another giddying spin to the moral wheel Dyer is bound to.

Naturally this has effects on the arguments. Take this from his intriguing chapter on lighting conventions in film and photography: "The argument here is that the photographic media are centrepieces in a whole culture of light that is founded on two particular notions, namely that reality can be represented as being on a ground of white, and that light comes from above; these notions have the effect not only of advantaging white people in representation and of discriminating between and within them, but also of suggesting a special affinity between them and the light". Even the solar system and electric light bulbs are in on the act, it seems, and the long history of artistic preference for a pale ground (demonstrated by artists of every race and colour) is evidence not of a common human biology (the eye) but of the cultural fossilisation of inegality.

It is clearly right that we (whoever we are, exactly) question what is taken as "normal" and "natural". But permanent suspicion has its own costs, not only in deforming the landscape into a series of potential atrocities, but also in denying everything that might be held in common. And this way of thinking doesn't just render academic study racked and tortured. Haringey Council currently issues a Guide to Activities for Under Eights, giving details of playgroups and swimming lessons. But its section on "Choosing Books" consists exclusively of "Five ways to analyse children's books for racism". This is what the pleasures of reading have been reduced to - a catechism of vigilance ("Look out for tokenistic illustrations") which identifies books as simply another territory of hurt. Surely you can be any colour under the sun and still feel that this is not a liberty but a novel kind of oppression?