Saturday, Ian McEwan's latest, chart-topping novel, unfolds on one, long day - February 15, 2003 - against the backdrop of the huge anti-war demo in London.

Henry Perowne, a top neurosurgeon, lives in a smart town-house with his wife Rosalind and son Theo. His whole family breathes success: Rosalind is an excellent lawyer, Theo a superb blues guitarist. Rosalind's father is an elderly poet of world-repute, and their daughter Daisy is about to be published, too.

They, like so many of us, have much to lose. Henry watches those who have less as they come and go beneath his window - the mad, screeching woman, the drug dealers, the users… He's safe from them, he hopes, in his kingdom - which extends to his Mercedes, in which he skims the streets to the sound of Vivaldi.

This Saturday is similar to all the others Henry loves and lives – he plays squash, visits his mother and buys the ingredients for a fish supper in 'gentle Marylebone'. Yet, as the critic Mark Lawson writes, ‘Saturday catalogues the local in order to focus on the global’.

The have-nots gatecrash Henry’s world, as a slow, sure day turns to terror with post-9/11 overtones. Henry is later to reflect that ‘the consequences of an action leap from your control and breed new events, new consequences, until you're led to a place you never dreamed of and would never choose...'

Along the way, Saturday provides plenty of food for the soul as well as the brain. McEwan asks 'Who am I?', for example, with skill and artistry through Henry’s nemesis, Baxter, who has Huntingdon's Disease: 'This is his dim, fixed fate, to have one tiny slip, an error of repetition in the codes of his being, in his genotype, the modern variant of a soul, and he must unravel.'

We're left to ponder the relationship between the wet, brilliantly circuited kilo of molecules called the brain, and our lot in life, in a tension that’s never resolved.

Ultimately, however, the question, 'Who is my neighbour?' is the subtle, yet unavoidable sub-text which makes Saturday a deeply moral story with no easy answers. We surely owe it to those on the outside looking in, like Baxter, to ponder it afresh from within our changing global and local contexts.

It’s only a simple question. And by asking it, what have we possibly got to lose?

Brian Draper

additional resources

Saturday was published in hardback last month by Jonathan Cape, 308pp, 2005.

Random House has a very useful 'reading group guide' with questions about the book - at www.randomhouse.com.

Read all the reviews at www.complete-review.com.

Ian McEwan's official website is atwww.ianmcewan.com.

"I work at 500 words a day and events were going at a million words a day. Then I saw that there was a significant moment in which nothing was resolved - the march itself - but into which everything else could be poured... It was very liberating - like deciding to write a sonnet." Read Boyd Tonkin's review and interview of McEwan in the Independent, at www.independent.co.uk.

Another interview about the book, this time in the Times: Jasper Gerard meets Ian McEwan, at www.timesonline.co.uk.

See the Damaris Trust's material on McEwan's previous, best-selling, award-winning book Atonement - at www.damaris.org.