On Beauty" is that rare comic novel about the divisive cultural politics of the new century likely to amuse readers on the right as much as those on the left. (Not that they'll necessarily be laughing in the same places.) Yet Smith is up to more as well: she wants to rise above the fray even as she wallows in it, to hit a high note of idealism rather than sink into the general despair. How radical can you be? Blame it on her youth.

Beautifully observed details of clothing, weather, cityscapes and the bustling human background of drivers, shoppers and passers-by are constantly being folded into the central flow of thought, feeling and action, giving even the most mundane moments - Levi riding a bus into Boston, Howard setting up a projector - a dense, pulsing life.

On Beauty is quieter. There is a complicated story making up by richness of implication what it lacks in exuberance. The culture of the Boston campus is set among the other cultures such a city harbours. Carl, the outsider who enters the story because of the muddle at the concert, is far from being a replica of Leonard Bast. He’s an exponent of rap culture – and it is a culture, unlike Bast’s pathetic aspirations. The power of his rap has to be explained, and indeed the author intervenes personally to endorse it: ‘the present-day American poets, the rappers’. The mufflered pink-cheeked charm of a New England campus in winter is very agreeably rendered. The row between Professor Belsey and Kiki when she finds out he’s been cheating is as deft as anybody could make it, he with his stumbling, evasive academic dialect and she with her ‘personal’ language and naturally inflexible notions of fidelity and honour.

In a late scene Kiki is sorting out her children’s accumulated belongings. As she is carrying two bags of her elder son’s ‘pre-growth-spurt clothes’, we are told:

Last year, she had not thought she would still be in this house, in this marriage, come spring. But here she was, here she was. A tear in the garbage bag freed three pairs of pants and a sweater. Kiki crouched to pick these up and, as she did so, the second bag split too. She had packed them too heavy. The greatest lie ever told about love is that it sets you free.

What makes this passage brilliant is that the sententia at the end, though it may be true, is somehow made ironical because it is Kiki, there among all the random evidence of her love, who is uttering it, and not some cheat, some intellectual, some person of recognised authority. She is the measure of Zadie Smith’s powers at 30, Forster’s age when he published Howards End.